3rd grade forces and motion

Question 1

True or false? Unbalanced forces can make an object start, stop, speed up or turn.

• A. True
• B. False

Question 2

Red team pulls left with 60 N, 90 N, 120 N. Blue team pulls right with 50 N, 60 N, 110 N. What is the size of the resultant (overall) force?

Answer N

Question 3

A box is pushed with 70 N to the left and 25 N to the right. What is the size of the resultant force, in newtons?

Answer N

Question 4

A sledge is at rest. It is pulled with 100 N to the left and 100 N to the right. What happens?

• A. it stays still
• B. it starts to move right
• C. it starts to move left

Question 5

A pendulum clock ticks once every second. How do clockmakers make a pendulum swing more slowly?

• A. make it shorter
• B. push it harder each time
• C. paint it gold
• D. make the pendulum longer

Question 6

Friction: which statement is NOT true?

• A. Bicycle brakes use friction to slow the wheels.
• B. Rough surfaces usually give more friction than smooth ones.
• C. Friction speeds things up.
• D. Friction can make surfaces warm up.

Question 7

A rolling ball slows down and stops on grass. Which force caused this?

• A. friction from the grass
• B. a push from the ball
• C. magnetism
• D. no force, it just ran out

Question 8

In a tug of war, the Red team's pullers pull with 50 N, 60 N, 110 N. What is the Red team's total pull?

Answer N

Question 9

A pendulum on a string takes 3 seconds to swing forward and back once. The pattern repeats. How many complete swings will it make in 9 seconds?

Answer 

Question 10

Why do football boots have studs?

• A. to reduce friction
• B. to make a noise
• C. to make them lighter
• D. to increase friction so players don't slip

Question 11

A toy car was rolled down the same ramp onto different surfaces. The chart shows how far it went (cm). Which surface had the LEAST friction?

• A. wood floor
• B. sandpaper
• C. ice
• D. carpet

Question 12

Red team (pulling left): 70 N + 70 N + 90 N. Blue team (pulling right): 40 N + 40 N + 100 N. What happens?

• A. Red team wins (rope moves left)
• B. nobody wins (balanced)
• C. Blue team wins (rope moves right)

Question 13

Balanced forces: which statement is NOT true?

• A. Forces are measured in kilograms.
• B. A book resting on a table has balanced forces acting on it.
• C. When forces are balanced, a moving object keeps moving at the same speed in the same direction.
• D. Forces are measured in newtons (N).

Question 14

Is this a contact force or a non-contact force: a magnet pulling a paperclip through paper?

• A. contact force
• B. non-contact force

Question 15

Three of these are examples of a contact force. Which one is NOT?

• A. a magnet pulling a paperclip through paper
• B. a rope pulling a boat
• C. kicking a ball
• D. pushing a door open

Question 16

True or false? Air resistance acts without anything touching.

• A. True
• B. False