Objects in Motion
What is the SI unit for speed?
m/s
According to Newton's Third Law, if you push on a wall with a force of 50N, the wall will push back with a force of _____.
50N
Newton
What does gravity pull objects toward?
The Earth
What is the formula for momentum?
p=mv
A car accelerates from 0 m/s to 20 m/s in 10 seconds. What is the car's acceleration?
2 m/s2
A person is sitting in a car that suddenly stops. The person keeps moving until they are stopped by the seatbelt. This happens because the person has ______.
Inertia (Newton's first law)
This type of force acts on an object when it is stretched or compressed
Elastic force
Would a 10kg object or a 100kg object experience more gravitational force?
100kg (the greater the mass, the greater the gravitational force)
What does momentum do to an object in motion?
Makes it hard to stop
What happens if a car has a negative acceleration?
It slows down
An object moves in a straight line at a constant speed. According to Newton's First Law of Motion, what will happen if no external force acts on it?
The object will continue moving at a constant speed
What type of friction is responsible for slowing down a rolling wheel on a surface?
Rolling friction
What happens when two objects of different masses fall from the same height in the absence of air resistance?
Both objects fall at the same rate (both objects will hit the ground at the same time)
A truck and a car are moving at the same speed. Which has more momentum?
The truck (it has more mass)
If a car travels 100 meters in 20 seconds, what is its speed?
5 m/s (s=d/t)
A skateboarder is pushing off the ground with their foot. As the skateboard moves forward, the ground exerts a force back on the skateboarder. This is an example of which law of motion?
Newton's third law
If a person pushes a shopping cart and the cart accelerates, are they exerting a balanced or unbalanced force on the cart?
Unbalanced
What is the primary factor that determines the amount of gravitational force between two objects?
The distance between objects
A car is driving down a road. If the driver suddenly slams on the brakes, what happens to the car's momentum?
The momentum decreases as the car slows down
A cyclist is traveling in a straight line. If the cyclist changes direction but maintains the same speed, what happens to its velocity? (Does velocity change or stay the same?)
The velocity changes (because direction is a factor in velocity)
A truck with a large mass accelerates more slowly than a small car when the same force is applied. Which of Newton's laws explains this?
Newton's second law (f=ma)
Air resistance is a type of _______.
Fluid friction
What would happen to an object's weight if it were moved to a location far from earth with less gravity (i.e. deep space)?
The weight would decrease (because weight is the force of gravity pulling downward on an object)
Two identical cars are driving on a highway. Car A is going 60 mph, Car B is going 30 mph. Which care has more momentum?
Car A