Question

15 POINTS !!!

1. Which of the following statements is correct for the work-kinetic energy theorem?

Wnet= change in potential energy

Wnet= change in kinetic energy

Wnet= change in elastic potential energy

Wnet= change in total energy


2. In which of the following cases is the torque greater? (see attachment)


3.


When a car makes a sharp left turn, what causes the passenger to move toward the right side of the car?


inertia


centripetal force


centrifugal force


centripetal acceleration


4. A 0.5 kg ball rolls down a frictionless inclined plane. The height of the inclined plane is 0.5m. What is the kinetic energy of the ball when it reaches the bottom of the inclined plane?


9.8 J


4.9 J


2.5 J


0.3 J

Answer 1

#1

As per work energy theorem work done by all forces must be equal to change in its kinetic energy

so correct answer will be

$W_{net}$ = change in kinetic energy

#2

Torque is defined as

$\tau = r \times F$

$\tau = rFsin\theta$

so here torque will be maximum when applied force is perpendicular to the rod

so first figure of rod is correct for maximum torque

#3

When car makes turn then its passengers moves outwards which is due to the property of inertia because due to this property passengers has tendency to move in same direction and hence it feels to move outwards

So correct answer will be

inertia

#4

As per energy conservation we can say

initial potential energy = final kinetic energy

$PE = KE$

$KE = mgH$

$KE = 0.5(9.8)(0.5)$

$KE = 2.5 J$