Alex is pushing on a box. Why doesn't the box move even though Alex is pushing on it?
The force of friction is balancing the force of Alex's push.
15
When a meteor gets near the Earth, it curves toward the Earth. Why doesn't the Earth curve toward the meteor?
Though they are both exerting equal gravitational forces on each other, the Earth is much more massive, and thus does not move.
15
You use a ping pong ball to knock your friends water bottle off their desk. The water bottle falls backward, but the ping pong ball also bounces back towards you. Why does this happen?
Newton's 3rd Law: The ping pong ball exerted a force on the water bottle, but the water bottle exerted a force back on the ping pong ball, pushing it back.
15
Based on the pictures of spring scales shown here, which object (A, B, C, or D) has the least weight?
A
15
Object A has a mass of 20 kg. Object B has a mass of 50 kg. If they are both pushed with the same force, which will accelerate faster?
Object A
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Object A and B both have a mass of 50 kg. If object A accelerates slower than object B, on which object was more force applied?
Object B
15
A frog jumps off of a lily pad, which is in the water, onto a rock. Which will move - the lily pad, the rock, or both, and in which direction?
The lily pad will move away from the rock.
15
What is the net force on the box in the picture?
100 N to the right
15
TRUE or FALSE: When two objects with different masses collide, only the larger object exerts a force on the smaller one, causing it to move.
FALSE - both objects exert equal and opposite forces on each other
15
You are riding in a car with your family. The car is going 50 km/hr. How fast are you moving relative to your family?
0 km/hr - you are all traveling at the same speed, so compared to them, you are not moving
15
Two equal forces are exerted in opposite directions on an object. Will the object accelerate?
No - the forces are balanced.
15
Two unequal forces are exerted in opposite directions on an object. Will the object accelerate?
Yes - the forces are unbalanced so the object will move in the direction of the stronger force.
15
A golfer uses his club to hit his ball across the green. Why does the ball accelerate away from the club more than the club moves away from the ball?
The ball has less mass, so the same amount of force that is applied to both causes the ball to move farther.
15
TRUE or FALSE: One golf ball is moving and one is still. When they collide, both balls exert forces on each other in opposite directions, even though one isn't moving.
TRUE
15
TRUE or FALSE: When a baseball is hit by a baseball bat, they exert equal and opposite forces on one another, which cancel each other out for a net force of 0.
FALSE: The forces are exerted on two different objects, so although there are equal and opposite forces applied, the effects do not cancel each other out.
15
Why is the front of a car designed to crumple during a crash?
It increases the amount of time it takes for the crash to happen, which decreases the acceleration, which decreases the amount of force from the impact.
