Vocab 1
A push or pull on an object
Force
this type of force cancels out and there is no change in movement
balanced forces
three people push piano with forces of 130 N to the right, 150 N to the left, and 165 N to the right. What is the strength and direction of the new force on the piano?
145 N to the right
the acceleration of an object is equal to the net force acting on the object divided by the objects mass
Newton's Second Law of Motion
Two toy cars that have the same mass and same speed move toward each other, collide, and stick together. After the collision, the momentum of the cars is _____.
half the original momentum
twice the original momentum
half the original momentum
The variable that represents force in an equation
F
Unbalanced forces can make an object accelerate by
changing its speed and/or direction
a child pushes down on a box lid with a force of 25N. At the same time, her friend pushes down on the lid with a force of 30N. The spring on the box lid pushed upwards with a force of 60N. Can the two kids push the box lid down? Explain.
No, their Net force is 55N and it takes more than 60N to close the lid.
if the net force on an object is zero, the motion of the object does not change.
Newton's First law of Motion
Whenever an object exerts a force on another object, the second object exerts a force of the same magnitude, but in the _____ direction to that of the first object.
opposite
The unit for force
Newton
sum of all forces
net force
a 24N net force acts on an 8kg rock. What is the acceleration of the rock?
3m/s2
when one object exerts a force on a second object, the second object exerts an equal force in the opposite direction on the first object
Newton's Third Law of Motion
A moving train car collides with another train car that is motionless on the track. The train cars are the same size. How does the final momentum of the two cars compare to the momentum of the first car?
it's double
it's the same
it's the same
An arrow can be used to represent a force. The length of the arrow represents
The strength of the force
can change the velocity of an object
unbalanced forces
A 30N net force on a skater produces and acceleration of 0.6m/s2. What is the mass of the skater?
50kg
A toy car has a forward push of 12N and a backward frictional force of 5N. Calculate the net force and state whether the forces are balanced or unbalanced.
7N Forward
unbalanced force
The relationship among force, mass, and acceleration is stated in ____.
the law of conservation of momentum
Newton's first law of motion
Newton's First Law of Motion
A student hits a nail with a hammer. During the collision, there is force exerted on what?
the nail and also on the hammer
the direction of acceleration is the same as the direction of __________.
Net force
What net force acting on a 14kg wagon produces an acceleration of 1.5m/s2.
21N
A car, has a friction force of 12N backward while the forward push is 19N. Calculate the net force and acceleration if the mass of car = 2.0kg.
Net force= 7N
Acceleration is 3.5m/s2
A ball with a momentum of 16 kg(m/s0 strikes a ball at rest. What is the total momentum of both balls after the collision?
16 kg(m/s)