Question

Question 21


When same vectors are in the same direction they add. When same vectors are in opposite directions, they:

a
subtract
b
divide
c
multiply
d
also add
Question 22


In the picture above, calculate the Net force for each force diagram. Choose the correct answer in order from top to bottom.

a
0 N, 20N, 2N
b
20N, 2N, 0N
c
0N, 2N, 20N
Question 23
Which of the following is an example of Newton's First Law?

a
Increasing the mass on an object experiencing the same force would decrease the acceleration
b
A rocket made with lighter composite materials will accelerate faster than a heavier one
c
A baseball hits collides with a fence and they exchange forces
d
A stationary book on the table must be picked up in order for it to move
Question 24
Susan gently pushes the tip of her finger against the eraser on her pencil and the pencil does not move. Which of the following figures best illustrates the interaction of forces between Susan’s finger and her pencil?

a




b




c




d




Question 25
Four students push on a block of wood with the forces shown in the diagram below. Assume friction is negligible.





What is the net force acting on the block? Are the forces balanced or unbalanced? How will the block move?

a
The net force on the block is 25 N. The forces are unbalanced. The block will move to the left.
b
The net force on the block is 25 N. The forces are unbalanced. The block will move to the right.
c
The net force on the block is 11 N. The forces are balanced. The block will move to the right.
d
The net force on the block is 11 N. The forces are unbalanced. The block will move to the left.
e
The net force on the block is 25 N. The forces are balanced. The block will move to the left.
f
The net force on the block is 11 N. The forces are balanced. The block will move to the left.
g
The net force on the block is 25 N. The forces are balanced. The block will move to the right.
h
The net force on the block is 11 N. The forces are unbalanced. The block will move to the right.
Question 26
An object is moving at a constant speed. If a balanced force is applied in the opposite direction the object is moving, what will most likely happen?

a
The object will speed up.
b
The object will continue moving at a constant speed.
c
The object will change direction.
d
The object will slow down and eventually stop moving.

Answer 1

Here are the answers:

Question 21: a (subtract)

Question 22: c (0 N, 2 N, 20 N)

Question 23: d (A stationary book on the table must be picked up in order for it to move — example of inertia / Newton’s 1st law)

Question 24: b (equal and opposite forces on the two objects — the finger pushes the pencil and the pencil pushes back)

Question 25: d (Net force = 11 N, forces are unbalanced, block will move to the left)

Question 26: d (The object will slow down and eventually stop moving.)