Answer:
v = 8.09 m/s
Explanation:
For this exercise we use that the work done by the friction force plus the potential energy equals the change in the body's energy.
Let's calculate the energy
starting point. Higher
Em₀ = U = m gh
final point. To go down the slope
Em_f = K = ½ m v²
The work of the friction force is
W = fr L cos 180
to find the friction force let's use Newton's second law
Axis y
N - W_y = 0
N = W_y
X axis
Wₓ - fr = ma
let's use trigonometry
sin θ = y / L
sin θ = 11/110 = 0.1
θ = sin⁻¹ 0.1
θ = 5.74º
sin 5.74 = Wₓ / W
cos 5.74 = W_y / W
Wₓ = W sin 5.74
W_y = W cos 5.74
the formula for the friction force is
fr = μ N
fr = μ W cos θ
Work is friction force is
W_fr = - μ W L cos θ
Let's use the relationship of work with energy
W + ΔU = ΔK
-μ mg L cos 5.74 + (mgh - 0) = 0 - ½ m v²
v² = - 2 μ g L cos 5.74 +2 (gh)
v² = 2gh - 2 μ gL cos 5.74
let's calculate
v² = 2 9.8 11 - 2 0.07 9.8 110 cos 5.74
v² = 215.6 -150.16
v = √65.44
v = 8.09 m/s
which form of energy is an example of kinetic energy
Answer:
1. realizing of arrow
2. kicking of ball
3. punching the punching bag
On a sunny day, a rooftop solar panel delivers 60 W of power to the house at an emf of 17 V. How much current flows through the panel
Answer:
3.53 amps
Explanation:
Given data
Power= 60W
Voltage= 17V
The expression relating current, power, and voltage is
P= IV
substitute
60= I*17
I= 60/17
I= 3.53 amps
Hence the current that flows is 3.53 amps
Two coils have the same number of circular turns and carry the same current. Each rotates in a magnetic field acting perpendicularly to its axis of rotation. Coil 1 has a radius of 4.5 cm and rotates in a 0.21-T field. Coil 2 rotates in a 0.39-T field. Each coil experiences the same maximum torque. What is the radius (in cm) of coil 2
Answer:
Explanation:
Torque acting on a coil in a magnetic field = MBsinθ where M is magnetic moment , B is magnetic field and θ is inclination of the normal to coil with direction of field.
For maximum torque sinθ = 1
Maximum torque = MB
M = NIA where N is no of turns , I is current and A is area of the coil
Maximum torque = NIAB
As maximum torque is same
N₁I₁A₁B₁ = N₂I₂A₂B₂
N₁ = N₂ , I₁ = I₂
A₁B₁ = A₂B₂
π R₁² B₁ = π R₂² B₂
4.5² x .21 = R₂² x .39
R₂² = 10.9
R₂ = 3.3 cm .
The skater lowers her arms as shown in the adjacent
figure decreasing her radius to 0.15 m. Find her new speed.
Answer:
is there more?
Explanation:
The average marathon runner can complete the 42.2-km distance of the marathon in 3 h and 30 min. If the runner's mass is 85 kg, what is the runner's average kinetic energy during the run
Answer:
the runner's average kinetic energy during the run is 476.96 J.
Explanation:
Given;
mass of the runner, m = 85 kg
distance covered by the runner, d = 42.2 km = 42,200 m
time to complete the race, t = 3 hours 30 mins = (3 x 3600s) + (30 x 60s)
= 12,600 s
The speed of the runner, v = d/t
v = 42,200 / 12,600
v = 3.35 m/s
The runner's average kinetic energy during the run is calculated as;
K.E = ¹/₂mv²
K.E = ¹/₂ × 85 × (3.35)²
K.E = 476.96 J
Therefore, the runner's average kinetic energy during the run is 476.96 J.
3. Batteries create electricity and generators create electricity. *
True
False
A straight wire in a magnetic field experiences a force of 0.026 N when the current in the wire is 1.5 A. The current in the wire is changed, and the wire experiences a force of 0.063 N as a result. What is the new current
Answer:
the new current on the wire is 3.64 A.
Explanation:
Given;
first force on the wire, F₁ = 0.026 N
second force on the wire, F₂ = 0.063 N
first current on the wire, I₁ = 1.5 A
second current on the wire, I₂ = ?
The force on a current carrying conductor placed in a magnetic field is given as;
[tex]F = BIL(sin \theta)\\\\[/tex]
F ∝ I
[tex]\frac{F_1}{I_1} = \frac{F_2}{I_2} \\\\I_2 = \frac{F_2I_1}{F_1} \\\\I_2 = \frac{0.063\ \times\ 1.5 }{0.026} \\\\I_2 = 3.64 \ A[/tex]
Therefore, the new current on the wire is 3.64 A.
can you please tell me what this is
Answer:
200000 J
Explanation:
From the question given above, the following data were obtained:
Mass (m) of roller coaster = 1000 Kg
Velocity (v) of roller coaster = 20 m/s
Kinetic energy (KE) =?
Kinetic energy is simply defined as the energy possess by an object in motion. Mathematically, it can be expressed as:
KE = ½mv²
Where
KE => is the kinetic energy.
m =>is the mass of the object
V => it the velocity of the object.
With the above formula, we can obtain the kinetic energy of the roller coaster as follow:
Mass (m) of roller coaster = 1000 Kg
Velocity (v) of roller coaster = 20 m/s
Kinetic energy (KE) =?
KE = ½mv²
KE = ½ × 1000 × 20²
KE = 500 × 400
KE = 200000 J
Therefore, the kinetic energy of the roller coaster is 200000 J.