A Stone thrown from the top of a building is given an initial velocity Of 20.0 metre per second straight upward determine the time in second at which the stone reaches its maximum height. ( Take sec2 g=9.8m/s)
A) 2.8
B) 2.04
C) 1.67
D) 2.7​

Answer:

v2 = 0.6 m/s in opposite direction

Explanation:

The computation of the speed of the raft is as follows

The center of system mass would be remains at the same place also it has no external force applied

Therefore

V = 0

So,  

M1.V1= - (M2.V2)

where,

M1 = 60 kg, V1 = 1.5 m/s

M2 = 150 kg

Now  

60 × 1.5 = - 150 × v2

v2 = -0.6 m/s

v2 = 0.6 m/s in opposite direction

Answer:

81

Explanation:

The problem here is to use the rules for significant figures in the multiplication below.

       67.6 x 1.2:

 This product will yield an answer that will produce the least number of significant figures.

   67.6 has 3 significant figures; 6, 7 and 6

    1.2 has 2 significant figures; 1 and 2

The product must give us an answer of two significant figures:

        67.6 x 1.2  = 81.12 to 2significant figures gives 81

The solution to this problem is 81

Answer:

Loop of Wire

Explanation:

By balancing the force, we get :

100 - Frictional Force = ma

100 - μmg = ma

100 - μ(5)(10) = (5)(15)

50μ = 25

μ = 0.5  

Distance travelled by box in 5 seconds is :

[tex]d = ut + \dfrac{at^2}{2}\\\\d = 0 + \dfrac{15\times 5^2}{2}\\\\d = 187.5\ m[/tex]

Hence, this is the required solution.

Answer:

the material of the phone case

The purpose of a cell phone cover is to protect your phone from impact forces. It is done by absorbing the impact of force by back cover.

What is Force ?

Force is responsible for the motion of an object. it produces acceleration in the body. According to newton's second law force is mass times acceleration i.e. F =ma. Its SI unit is N which is equivalent to kg.m/s².

The case is made in such a way that, if the cell phone is dropped, the cover will absorb the kinetic energy of the falling phone by the means of deforming without transferring the impact onto the phone.

Cell phone cover is made up of rubber which can restore the forces like a spring. when u apply force to the rubber it get displaced and applied force is stored in the rubber. when cell phone drops, rubber of the cover absorbs the energy of impact. it also provides shied protection to the phone.

Hence this is how cell phone case do this.

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We have that the work the engine did is

w=1710000J

From the Question we are told that

Power  P=190,000 W

T= 9 s

Generally the equation for the work   is mathematically given as

[tex]w=pt\\\\w=190,000*9s\\\\w=1710000J[/tex]

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Answer:

2.47 s

Explanation:

Convert the final velocity to m/s.

We have the acceleration of the gazelle, 4.5 m/s².

We can assume the gazelle starts at an initial velocity of 0 m/s in order to determine how much time it requires to reach a final velocity of 11.1111 m/s.

We want to find the time t.

Find the constant acceleration equation that contains all four of these variables.

Substitute the known values into the equation.

The Thompson's gazelle requires a time of 2.47 s to reach a speed of 40 km/h (11.1111 m/s).

Answer:

B: A  material with relatively weak bonds between it's particle can be shped in to a thin sheet.

Explanation:

Answer:

The force of friction acting on the block has a magnitude of 15 N and acts opposite to the applied force.

Explanation:

Net Force

The Second Newton's law states that an object acquires acceleration when an unbalanced net force is applied to it.

The acceleration is proportional to the net force and inversely proportional to the mass of the object.

If the object has zero net force, it won't get accelerated and its velocity will remain constant.

The m=2 kg block is being pulled across a horizontal surface by a force of F=15 N and we are told the block moves at a constant velocity. This means the acceleration is zero and therefore the net force is also zero.

Since there is an external force applied to the box, it must have been balanced by the force of friction, thus the force of friction has the same magnitude acting opposite to the applied force.

The force of friction acting on the block has a magnitude of 15 N opposite to the applied force.

Answer:

Jennifer

Explanation:

she has more mass which means she is using more force

Answer:

When the student slides the rock along the flat surface of the frozen pond, according to Newton's second law of motion, the rock is given an initial velocity of motion. According to Newton's first law of motion, the rock will continue to slide indefinitely unless it is slowed or stopped by an opposite force. According to Newton's third law, the rock experiences a reaction force from the force of friction of the ice which slows it down at a rate given by Newton's second law of motion and the rock is seen to decelerate

Explanation:

Newton's first law of motion, states that an object will remain at rest or maintain a uniform motion in a straight line, unless impressed upon by an external force

Newton's second law states that an applied force is equal to the rate of change of momentum it produces

Newton's third law states action and reaction are equal and opposite.

Answer:

See the explanation.

Explanation:

Q9. Irregular reflection happens when a set of parallel beams are reflected from non-smooth surface which results in non-parallel reflected beams.

Q10.

i) Periscope

ii) There are different types of periscopes but the main characteristic of this instrument is observation over the obstacles or in general objects that are not in the line-of-sight. Basic Periscope uses parallel angled mirrors to project objects that are above the surface in submarines.

Answer:

If you haven't heard, Joe Biden would like to unite America.

It was a focus of the Democrat's campaign. It's even the theme of Biden's inauguration — "America United."

The inaugural committee says the slogan "reflects the beginning of a new national journey that restores the soul of America, brings the country together, and creates a path to a brighter future."

If only it were that easy.

When Biden is sworn in at 12:01 p.m. ET Wednesday as the 46th president of the United States, it will be with the understanding that the country is as divided as it's ever been, as pessimistic as it's been in three decades and facing health, economic and racial crises.

It will also be a very different inauguration than has ever been seen in U.S. history. Four years ago, President Trump was arguing over his crowd size compared with Barack Obama's record-setting turnout of supporters on the National Mall.

Explanation:

btw i would rather have him as president

Answer:

hello the diagram related to this question is missing attached below is the missing diagram

Answer :

The magnitude of the electric field = 4KQ / L^2

direction = 45° east to south

Explanation:

The magnitude of the electric field = 4KQ / L^2

direction = 45° east to south

Answer:

The cyclist's average speed is 13.43 [tex]\frac{km}{h}[/tex]

Explanation:

Speed ​​is a quantity that expresses the relationship between the space traveled by an object and the time used for it. That is, speed is the magnitude that expresses the variation in position of an object and as a function of time, which would be the same as saying that it is the distance traveled by an object in the unit of time.

Average speed relates the change in position to the time taken to effect that change:

[tex]speed=\frac{change in position}{time} =\frac{distance}{time}[/tex]

In this case:

Replacing:

[tex]speed=\frac{47 km}{3.5 h}[/tex]

and solving, you get:

speed= 13.43 [tex]\frac{km}{h}[/tex]

The cyclist's average speed is 13.43 [tex]\frac{km}{h}[/tex]

Answer:

Not accounting for friction, the ball would be falling at 14.0 m/s

Explanation:

Without a coefficient of kinetic friction being provided, we'll have to assume zero friction between the ball and the air.

In that case, the ball's horizontal speed will remain 10 m/s.  To find it's velocity in five seconds then, we just need to take gravity into account.

Let's assume acceleration from gravity is 9.8 m/s².  We can simply multiply that by five seconds to find out how fast it's going at that point:

[tex]9.8\frac{m}{s^2} \times 5s\\= 49 \frac{m}{s}[/tex]

So at five seconds, the ball is moving horizontally at 10 m/s and vertically at 479 m/s.

Now we can simply take the hypotenuse between those two vectors to get the actual speed:

[tex]s = \sqrt{9.8^2 + 10^2}\frac{m}{s}\\s = \sqrt{96.04 + 100}\frac{m}{s}\\s = \sqrt{196.04}\frac{m}{s}\\s = 14.0 \frac{m}{s}\\[/tex]

So lacking air to slow it down, the ball would be going at approximately 14.0 metres per second.

Answer: it is actually B. :)

Explanation:

Noise can distort analog signals making them unreliable.

Noise can actually bury, distort or cause interference to the analog signal carrying the intelligent information.

Hence, the correct answer is B.

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Answer:

Earth is nearest the Sun in July and farthest away in July.

Explanation:

Answer:

Correct Answer: B.

Explanation:

Earth is nearest the Sun in January and farthest away in July. Explanation: According to Kepler's Second Law, a planet travels fastest when it is nearest its sun. This means that Earth is actually closest to the Sun in January, when it is winter in the northern hemisphere!