(Multiple Choice)

­­(1)

A baseball player hits a ball with a bat. If the force with which the bat hits the ball is considered the action force, what is the reaction force? 

(a) The force the bat exerts on the batter’s hands. 

(b) The force on the ball exerted by the glove of the person who catches it. 

(c) The force the ball exerts on the bat. 

(d) The force the pitcher exerts on the ball while throwing it. 

(e) Friction, as the ball rolls to a stop.

(2)

Which of the free-body diagrams in Figure 4-26 represents a block sliding down a frictionless inclined surface?

(3)

A lamp with a mass m = 42.6 kg is hanging from wires as shown in Figure. The tension T₁ in the vertical handle is 

(a) 209 N. 

(b) 418 N. 

(c) 570 N. 

(d) 360 N. 

(e) 730 N.

(4)

A 40.0-kg object supported by a vertical rope is initially at rest. The object is then accelerated upward. The tension in the rope needed to give the object an upward speed of 3.50 m/s in 0.700 s is 

(a) 590N. 

(b) 390N. 

(c) 200N. 

(d) 980 N. 

(e) 720 N.

(5)

A hovering helicopter of mass m_h is lowering a truck of mass m_t. If the truck's downward speed is increasing at the rate 0.1g, what is the tension in the supporting cable? 

(a) 1.1m_tg 

(b) m_tg 

(c) 0.9m_tg 

(d) 1.1(m_h + m_t)g 

(e) 0.9(mh + mt)g

(6)

A horse-drawn coach is decelerating at 3.0 m/s² while moving in a straight line. A lamp of mass 0.844 kg is hanging from the ceiling of the coach on a string 0.6 m long. The angle that the string makes with the vertical is 

(a) 8.5° toward the front of the coach. 

(b) 17° toward the front of the coach. 

(c) 17° toward the back of the coach. 

(d) 2.5° toward the front of the coach. 

(e) 0° or straight down.

(7)

The system shown in Figure is in equilibrium. It follows that the mass m is 

(a) 3.5 kg. 

(b) 3.5 sin 40° kg. 

(c) 3.5 tan 40° kg. 

(d) None of the above.

(8)

An object is suspended from the ceiling of an elevator that is descending at a constant speed of 9.81 m/s. The tension in the string holding the object is

(a) Equal to the weight of the object. 

(b) less than the weight of the object but not zero. 

(c) greater than the weight of the object.

(d) zero

Transcribed Image Text:

(d) (b) (a) (c)