Answer:
Fossil fuels take millions of years to replenish
Answer:
Fossil Fuel is limited it is like coal there is a limit and it won't last forever. This also contributes that it is not safe for the environment as well as the safety and health of people. This is similar to when there are many factories around an area there is going to be a high percentage of respiratory diseases such as asthma.
A rocket sled accelerates forward from 10 m/s to 50 m/s in 2 seconds. What is the acceleration of the sled?
Answer:
Explanation:
Use kinematics equations
You have Vi=10m/s and Vf=50m/s and t=2s
Use equation Vf=Vo+at 50=10+a(2)
50=10+2a
40=2a
a=20 m/s^2
A force of 1200N is creating a pressure of 60Pa on a surface. Calculate the area of the surface.
Answer: 20 squared units
Explanation:
Area = Force / Pressure
Which is greater 45 RPM or 4.71 rad/s? Why?
45 rpm is greater/faster. Convert both measurements to the same unit rate:
45 rpm = (45 rev) / (1 min) = (45 rev) / (60 s) = 0.75 rps
4.71 rad/s = (4.71 rad) / (1 s) • (1 rev) / (2π rad) = (4.71 rev) / (2π s) ≈ 0.74962 rps
If a ball that is 10 meters above the ground is thrown horizontally at 5.51 meters per second. a. how long will it take for the ball to hit the ground? b. how far will the ball travel in the horizontal direction before it hits the ground?
Answer:
a. t = 1.43 s
b. d = 7.88 m
Explanation:
a. The time of flight can be found using the following equation:
[tex] y_{f} = y_{0} + v_{0_{y}}t - \frac{1}{2}gt^{2} [/tex]
Where:
[tex]y_{f}[/tex]: is the final height = -10 m
[tex]y_{0}[/tex]: is the initial height = 0
[tex]v_{0_{y}}[/tex]: is the initial speed in the vertical direction = 0
g: is the acceleration due to gravity = 9.81 m/s²
By solving the above equation for "t" we have:
[tex] t = \sqrt{\frac{2y_{f}}{g}} = \sqrt{\frac{2*10 m}{9.81 m/s^{2}}} = 1.43 s [/tex]
Hence, the ball will hit the ground in 1.43 s.
b. The distance in the horizontal direction can be found as follows:
[tex] x_{f} = x_{0} + v_{0}t + \frac{1}{2}at^{2} [/tex]
Where:
x₀: is the initial position in the horizontal direction = 0
a: is the acceleration in the horizontal direction = 0 (it is moving at constant speed)
[tex] x_{f} = 5.51 m/s*1.43 s = 7.88 m [/tex]
Therefore, the ball will travel 7.88 m before it hits the ground.
I hope it helps you!
A 2-inch, f/4 reflector has a focal length of:
6 inches
8 inches
4 inches
2 inches
Which of the following instruments measures time most accurately?
a. Sundial
b. quartz watch
c. pendulum clock
d. watch with balance wheel
Answer:
b) Quartz Clock
Explanation:
It's is a very type of clock which uses the vibration of quartz crystals to measure time accurately
Two rocks of masses 5 kg and 10 kg a dropped from rest from a height of 20 m above ground. Ignore all friction and air resistance. Just before
they hit the ground, which statement is true about the rocks?
(A) The value for the acceleration of the 5 kg rock is the same as the value for the 10 kg rock, but their velocity values are different.
(B) The values for the acceleration and velocity of the 5 kg rock are greater than the values for the 10 kg rock.
(C) The values for the acceleration and velocity of the 5 kg rock are less than the values for the 10 kg rock.
(D) The values for the acceleration and velocity of the 5 kg rock are the same as the values for the 10 kg rock.
Answer:
D
Explanation:
F=ma
F of 5 kg rock = 49N
F of 10 kg rock = 98 N
Divide by respective masses to get acceleration, and of course you will get 9.8 m/s^2 for both.
Now, use potential energy equals kinetic energy. mgh=(1/2)mv^2 mass cancels out of the equation, since it's on both sides, so we can stop right there. We have algebraically determined that mass does not affect acceleration or velocity!
Hope this helped.
A power source of 6.0 V is attached to the ends of a
capacitor. The charge is 12 C.
Why is the Greenland ice sheet so important to understanding earths past climate?
Answer:
The ice sheet as a record of past climates
Scientists have, using those ice cores, obtained information on (proxies for) temperature, ocean volume, precipitation, chemistry and gas composition of the lower atmosphere, volcanic eruptions, solar variability, sea-surface productivity, desert extent and forest fires.
Answer:
The Greenland ice sheet is the last remaining ice sheet from the most recent ice age. Therefore, it can tell scientists about the climate conditions of that period.
Explanation:
Find the gravitational force between Venus (4.87 x 1024 kg) and
the sun (1.989 x 100 kg). Venus orbits at a distance of
1.082 x 10" m.
The gravitational force between Venus and the Sun, seperated at the distance of 1.082×10¹¹ m is 5.520×10²² N.
What is gravitational force?Gravitational force is the attractive force between two bodies. It is applicable to all the bodies have masses and it is called as Universal law of gravitation.
Grarvitational force is the attractive force is directly proportional to the product of two masses and is inversely proportional to the square of distance between them.
F ∝ m₁ × m₂ / d², m₁ and m₂ is the mass of two bodies and d² is the distance between two bodies. The SI unit of mass is kg and SI unit of distance is m. The SI unit of force is newton.
From the gravitational force,
F = G (m₁×m₂ / d²)
G represents gravitational constant and is equal to 6.67× 10⁻¹¹ N.m²/kg².
From the given,
m₁ ( mass of venus ) = 4.87 x 10²⁴kg
m₂ ( mass of sun) = 1.989 x 10³⁰ kg
d² ( distance between sun and venus) = 1.082 x 10¹¹ m.
G = 6.67 ×10⁻¹¹ N.m² / kg²
F = G (m₁×m₂ / d²)
= 6.67 ×10⁻¹¹ × 4.87 x 10²⁴× 1.989 x 10³⁰ / (1.082 x 10¹¹)²
= 5.520 × 10²² N
The gravitational force between the venus and sun at the distance of 1.082 x 10¹¹ is 5.520× 10²² N.
To learn more about the Gravitational force:
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As your scooter coasts downhill, your speed goes from 4 m/s to 6 m/s in 1.5
seconds. What is your acceleration?
A. 2.4 m/s
B. 1.3 m/s
C. 0.8 m/s
D. 3.0 m/s
Answer:
it is B.
Explanation:
An object is moving to the right at a constant velocity. What will happen if a
force of 20 N starts acting on it in the opposite direction?
А The object's velocity will increase.
B
The object's velocity will decrease.
с
The object will come to a stop.
D
The object will move at the same velocity.
A piece of wire length 30cm and cross sectional area of 0.5mm^2 has a resistance of 5ohms at 20°c. It is then heated to a temperature of 150°c. Calculate it's resistivity at 20°c
Answer:
8.333*10^-6 ohms
Explanation:
Resistivity of a material is expressed as;
p = RA/l
R is the resistance of the material
A is the cross sectional area
l is the length of the material
Given
R = 5 ohms
A = 0.5mm^2
A = 5 * 10^-7m^2
l = 30cm = 0.3m
Substitute into the formula;
p = (5 * 5 * 10^-7m^2)/0.3
p = 25 * 10^-7/0.3
p = 0.0000025/0.3
p = 8.333*10^-6
Hence its resistivity at 20 degrees Celsius is 8.333*10^-6 ohms
A wave frequency of 440 Hz travels through a medium at 343 m/s. Calculate the wavelength
for this wave.
150,920 m
1.28 m
97 m
0.078 m
Answer:
0.78 m
Explanation:
us the formula
speed = frequency x wavelength
343 = 440 x wavelength
343 / 440 = wavelength
wavelength = 0.78 m
I think the last option, you wrote wrongly, it is supposed to be 0.78 not 0.078 .
if you think I am wrong please do tell me, I will redo this.
hope this helps
Please help!!!!!!!!
Answer:
Option C. 83.8 J
Explanation:
From the question given above, the following data were obtained:
Mass (m) of object = 2 Kg
Velocity (v) of the object = 5 m/s
Height (h) = 3 m
Mechanical energy =.?
Next, we shall determine the kinetic energy of the object. This can be obtained as shown below:
Mass (m) of object = 2 Kg
Velocity (v) of the object = 5 m/s
Kinetic energy (KE) =?
KE = ½mv²
KE = ½ × 2 × 5²
KE = 1 × 25
KE = 25 J
Next, we shall determine the potential energy of the object. This can be obtained as shown below:
Mass (m) of object = 2 Kg
Height (h) = 3 m
Acceleration due to gravity (g) = 9.8 m/s²
Potential energy (PE) =.?
PE = mgh
PE = 2 × 9.8 × 3
PE = 58.8 J
Finally, we shall determine the mechanical energy of the object. This can be obtained as shown below:
Kinetic energy (KE) = 25 J
Potential energy (PE) = 58.8 J
Mechanical energy =?
Mechanical energy = KE + PE
Mechanical energy = 25 + 58.8
Mechanical energy = 83.8 J
which material would you select to replace broken handle of electric kettle
please will mark as brainlist
Answer:
hot glue
Explanation:
-insert the hot melt cylinder into the gun and wait until it heats up;
-gently apply a layer of substance to the crack;
-spread the hot glue in a thin layer over the surface;
-wait until it freezes.
pls help, i really dw fail :(
Answer:
Using the Newton equation
V²=U² +2as
Given; V=9.2m/s U = 0m/s( because it starts from rest)
S=26.2m.
9.2²=0²+2(26.2)a
a =9.2²/2(26.2)
a=84.6/52.4
a=1.60m/s²
Answer:
2.A
3.D
Explanation:
HOPE THIS HELPS!! :)
Elements with positive valences usually ______ electrons
A. Donate
B. Accept
C. Have no
D. Create
someone help please !!
Answer:
c.
is the answer please brainliest
What is the object’s average acceleration between 0.0 s and 5.0 s?
ANSWER FAST! PLEASEE
Answer:
[tex]2.5[/tex]
Explanation:
[tex]0.0+5.0=5.0[/tex]
[tex]\frac{5}{2} =2.5[/tex]
hope this helps!!!!!!!!!!
Which location, 23 degrees or 48 degrees would experience the same earthquake at stronger intensity?Explain why.
Answer:
48 degress
Explanation:
An earthquake causes many different intensities of shaking in the area of the epicenter where it occurs. So the intensity of an earthquake will vary depending on where you are. Sometimes earthquakes are referred to by the maximum intensity they produce. In the United States, we use the Modified Mercalli Scale. Earthquake intensity is a ranking based on the observed effects of an earthquake in each particular place. Therefore, each earthquake produces a range of intensity values, ranging from highest in the epicenter area to zero at a distance from the epicenter.
Objects that are able to roll have what type of energy?
A. potential
B. mechanical
C. thermal
D. chemical
An archer uses 2000J of energy to pull a bow string 0.15m. What is the force constant (k) of the bow string?
The spring constant of the given bow spring is equal to 1.77 × 10⁵ N/m.
What is Hooke's law?Hooke's law can be described as a law that states that the force (F) required to extend or compress a spring by displacement linearly with respect to that displacement along a straight line.
The spring force can be represented in the form of an equation:
F = -kx
where k is a spring constant of the spring and x is the deformation of the spring. The negative sign shows that force is restoring force.
The energy that can be stored in the spring when it is stretched is given by:
E = (1/2)kx²
Given, the energy stored in the spring when it is stretched, E = 1000J
The distance by which the bow spring is stretched, x = 0.15 m
2000 = (1/2) × k (0.15)²
k = 1.77 × 10⁵ N/m
Learn more about Hooke's law, here:
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What is the current if a charge of 25 coulombs passes in 5 seconds?
Answer: 5 amps
Explanation: I = Q/t
How is a mixture different from a compound?
Answer:
MIXTURE
1 In a mixture two or more substances are mixed together (elements or compounds)
2Therd is no fixed proportion of the constituents
3 The mixture may or may not be homogenous
4 There is no chemical reaction between the constituent substances
5 There cannot be a chemical formula for a mixture
6 Heat or any other type of energy is not required or released during the formation of a mixture
7 The constituents can be separated using simple physical processes
8 The properties of the constituents are retaied
COMPOUND
1 Two or more elements form a compound
2 The constituent elements combine in a definite proportion to form a compound
3 The elements are in a definite proportion in any part or fraction of the compound
4 There is a chemical reaction in the formation of a compound
5 A compound has always a chemical formula for a compound
6 Heat orany other energy is often required for the formation of a compound or released during the formation of a compound
7 The constituent elements can't be separated using simple physical processes in case of a compound
8 The properties of the constituent elements are not retained in the compound
The brakes of a 2000 kg car apply a force of 250 N to slow down a car as it comes off of an exit ramp. What is the acceleration of the car?
What's a real-life example of Newton's Second Law?
3 Describe the two possible things that can happen if a charged object is brought near
another charged object,
4 Give one example of a balloon repelling another object, Explain why the balloon repelled
the object
Answer:
For two objects of charges q1 and q2, that are separated by a distance R, the force that each object suffers is given by the Coulomb's:
F = k*q1*q2/R^2
If both charges have the same sign, then we have a positive force, which means that the objects are "pushing" each other, then this is a repulsive force.
If instead, each object has a charge with a different sign, the force will be negative, then the objects will be pulling each other, and the force is an attractive force.
a) Whit this in mind, the two possible things that can happen if a charged object is near another charged object are:
The objects repel each other, which happens when both objects have charges with the same sign.
The objects attract each other, which happens when the objects have charges with a different sign.
b) A charged balloon most probably has a static charge (the type of charge that can be obtained by rubbing the balloon with a piece of cloth), which means that it has extra electrons, and we know that electrons have a negative charge, then we can assume that this balloon has a negative charge.
Then if we put another charged balloon (also with static charge) near our original balloon they will repel each other, this happens because both balloons have a negative charge.
physics help me pleaseee
Answer:
letter e.
Explanation:
because i know its not too deep
What is the frequency of a raido wave with a wavelength of 1.0 mm?
Answer:
3×10^6
Explanation:
frequency is the speed of light ( c) which is a constant number divided the wavelength
f = 3×10^6 / 1.0