Draw a free body diagram for the sprinter

Gravity pulling down

Starting blocks pushing, ⊥ to the blocks

Friction dragging on shoes, ‖ to the blocks

The sprinter accelerates because the contraction of their leg muscles causes there to be large friction and normal forces from the starting blocks.

F⃗Gf⃗s

n⃗

f⃗s

n⃗

What is the free body diagram for the box on the ramp?Assume that the box is neither moving nor accelerating (i.e. it is stationary).

F⃗G

n⃗f⃗s

F⃗G

n⃗f⃗s

F⃗G

n⃗

(a) (b) (c)

F⃗G

n⃗f⃗s

(d)

Two stacked boxes sit motionless on a ramp. What is the free body diagram for the lower box?

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

F⃗G

n⃗1

f⃗s,1f⃗s,2

n⃗2

F⃗G

n⃗1f⃗s,1

f⃗s,2

n⃗2F⃗G1

n⃗1f⃗s,1

f⃗s,2F⃗G

n⃗1f⃗s,1

f⃗s,2 n⃗2F⃗G2

The person is swinging forward. Consider the following possible forces on the person:

1. “A force straight down”2. “A force up the rope”3. “A force in the direction of motion”4. “A force away from the rope”

(a) 1 only(b) 1 and 2(c) 1 and 3(d) 1, 2 & 3(e) 1, 3 & 4

Which of these is present?

1

2

3

4

A net force on a body causes the body to accelerate in the same direction as the net force. The amount of acceleration is inversely proportional to the “mass”.

~a =~Fnet

m=

~F1 + ~F2 + ~F3 + · · ·m

=

Pi~Fi

m

~Fnet = m~a

The net force at tim

e t is related to the

acceleration at time t; is has nothing

to do with the velocity at time t,!

An object being pushed by three forces is accelerating to the right. Two of the forces are pictured below. Which of the examples below might be the 3rd force?

(a) (b) (c) (d) (e) None of these

F⃗1F⃗2

You toss a ball straight up. Just after it has left your hand, which is the appropriate free body diagram (ignoring air resistance)?

(a) (b) (c) (d) (e) None of the above

(a) Larger(b) Smaller(c) Equal(d) Depends on v

An elevator is lifted at a constant speed by a cable attached to a motor. Consider a passenger inside the elevator. Compared to the downward force of gravity on the passenger, the upward force exerted on her feet by the floor of the elevator is…

v

An elevator is nearing the top floor of a building and hence is slowing down. The appropriate free body diagram for the passenger in this situation is:

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

(e) None of the above

An elevator is arriving on the ground floor. Just before the elevator stops, the appropriate FBD for the passenger is:

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

(e) None of the above

http://www.ynaija.com/faith-the-dangers-of-secular-feminism/

(a) ½T (b) T (c) 2T

What does this scale read for the tension?

http://www.alibaba.com/product-gs/203306901/Spring_Dial_Hoist_Scale/showimage.html

Scale reads a tension force T

A rocket in the depths of space (no gravity, no air... no external forces) moves forward at constant speed. It applies a thruster which provides a constant horizontal force for a few seconds (the dashed path), then turns it off. Which of the paths below could the rocket follow?

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

(e) None of the above