Answer:
- 5436 J
Explanation:
mass of car, m = 120 kg
radius of loop, r = 12 m
velocity at the bottom (A) = Va = 25 m/s
Velocity at the top(B) = Vb = 8 m/s
Vertical distance from A to B = diameter of loop, h = 2 x 12 = 24 m
by use of Work energy theorem
Work done by all the forces = change in kinetic energy of the body
Work done by the force + Work done by the friction = Kinetic energy at B - kinetic energy at A
- m x g x h + Work done by friction = 0.5 x 120 x (Vb^2 - Va^2)
- 120 x 9.8 x 24 + Work done by friction = 60 x (64 - 625)
- 28224 + Work done by friction = - 33660
Work done by friction = -33660 + 28224 = - 5436 J
1. Answer: 7.75 seconds
Explanation: 76-14=62 metres
62/8=7.75 seconds
2. Answer: 2.5 seconds
Explanation: 28-18=10 metres
10/4=2.5 seconds
Answer:
Work done, W = 19.6 J
Explanation:
It is given that,
Mass of the block, m = 5 kg
Speed of the block, v = 10 m/s
The coefficient of kinetic friction between the block and the rough section is 0.2
Distance covered by the block, d = 2 m
As the block passes through the rough part, some of the energy gets lost and this energy is equal to the work done by the kinetic energy.
W = 19.6 J
So, the change in the kinetic energy of the block as it passes through the rough section is 19.6 J. Hence, this is the required solution.
Answer:
2.4s
Explanation:
The length of the pendulum = 75ft
Diameter d = 12 inches
The time period of the pendulum is given as
T = 2pi(L/g)^1/2
Then the time it takes to move from displacement to equilibrium is given as:
t = T/4
= (Pi/2)*(L/g)^1/2
= pi/2 x [(75x0.3048)/9.81]^0.5
= 1.57x[22.86/9.81)^0.5
= 2.4s
2.4 seconds is the least amount of time that it would take.
Neutron is commonly used to initiate a fission chain reaction.
