In our experience objects must be pushed to keep moving. So a force would be necessary to have a constant velocity.
Who is Aristotle
100
An object at rest remains at rest and an object in motion remains in motion unless acted on by an external force
What is Newton's First Law
100
Newton's Second Law identifies the relationship between what?
What is mass and acceleration
100
A key to the correct application of the third law is that the forces are exerted on different objects. Why should you make sure that you don't use them as if they were acting on the same objects.
What is they would add up to zero.
100
The reason it is difficult to push a heavy box along the floor
What is friction
200
Scientist who imagined a world where friction would be eliminated.
Who is Galileo and Newton
200
The tendency of an object to resist any change in motion
What is inertia
200
A 3.5 kg object experience an acceleration 0.5 m/s^2. What net force does the object experience?
What is (3.5kg) * (0.5m/s^2) = 1.75 N
200
An object of mass m sits on a flat table. The earth pulls on this object with force mg, which we will call the action force. What is the reaction force?
What is The object pulling upward with a force mg
200
A brick is sliding to the right on a horizontal surface. What are the directions of the two surface forces: the friction force and normal force?
What is left, up
300
He concluded that objects remain at rest or they remain in motion unless acted on by an external force.
Who is Issac Newton
300
When you sit on an object the net external force on you is?
What is zero
300
A 12 Newton net force acts on a 36 kg object? How much does it accelerate?
What is (12) * (36) = 0.33 m/s ^2
300
A 20 ton truck collides with a 1500-lb car and causes a lot of damage to the car. Since a lot of damage is done on the car which had the greater force?
What is the force on the truck is equal to the force on the car.
300
A 4 kg brick is sliding on a surface. The coefficient of kinetic friction between the surfaces is 0.25. What is the size of the force of friction?
What is (0.25) *(4)* (9.8) = 9.8 N
400
Scientists who imagined a world where friction would be eliminated
Who are Newton and Galileo.
400
A rocket moves through empty space in a straight line with constant speed. It is far from the gravitational effect of any star or planet. Under these conditions, the force that must be applied to the rocket in order to sustain its motion is ?
What is no force needed
400
A ball strikes a 0.145 kg baseball with force of 5800 N. What acceleration does the baseball experience?
What is (5800)/(0.145) = 40,000 m/s ^2
400
As you are sitting in a chair, you feel the chair pushing on you. The reaction force in this situation is
What is you pushing down on the chair.
400
A 4.0 kg brick is sitting on a table. The coefficient of static friction between the surface is 0.45. What is the largest force that can be applied horizontally to the brick before it begins to slide?
What is (0.45) * (4) *(9.8) = 17.64
500
Scientist who questioned Newton's work in optics and was his rival. he also helped Newton in discovering gravity
Who is Robert Hooke
500
You are standing in a moving vehicle, facing forward, and you suddenly fall forward. You can infer from this that the bus's
velocity decreased
500
A 5 kg object is being acted on by a 20 N force to the right (F1), and a 30 N force, also to the right (F2. What is the net force on the object.
20N + 30N = 50 N to the right.
500
A student is doing a hand stand. A reaction pair of forces is best described as:
What is a student pushing down on the ground - The ground pushing up on the student.
500
A 50 kg crate is pushed across a warehouse floor with a force of 100 N, accelerating at a rate of 1 m/s^2. What is the coefficient of friction between the floor and crate?