Physics Mechanics 4

Question 1

A satellite orbits Earth in a circular orbit. Which force provides the centripetal acceleration?

Accepted Answer

Gravity from Earth

Answer

The satellite's engine thrust

Answer

Air resistance

Answer

Normal force from the atmosphere

Question 2

A 4 kg object moves in a horizontal circle of radius 2 m at a speed of 3 m/s. What is the centripetal force acting on it?

Accepted Answer

18 N

Answer

6 N

Answer

36 N

Answer

9 N

Question 3

What happens to the period of a simple pendulum if its length is quadrupled?

Accepted Answer

It doubles

Answer

It quadruples

Answer

It halves

Answer

It remains the same

Question 4

A 1500 kg car traveling at 30 m/s brakes to a stop. How much work does friction do on the car?

Accepted Answer

−675,000 J

Answer

675,000 J

Answer

−45,000 J

Answer

45,000 J

Question 5

Two identical balls collide head-on elastically with equal speeds. What happens after the collision?

Accepted Answer

Both balls rebound with their original speeds reversed

Answer

Both balls stop

Answer

One ball stops and the other moves at double speed

Answer

Both balls move in the same direction

Question 6

A force of 50 N is applied at an angle of 60° to the horizontal to push a box across the floor. What is the horizontal component of this force?

Accepted Answer

25 N

Answer

43.3 N

Answer

50 N

Answer

86.6 N

Question 7

Which of the following statements about kinetic friction is correct?

Accepted Answer

Both B and C

Answer

It depends on the speed of the sliding object

Answer

It is always less than static friction for the same surfaces

Answer

It is independent of the contact area for flat surfaces