Vocab, Vocab, Vocab
A property of any moving object; equals the object's mass times its velocity.
Momentum
In the absence of air, a penny and a feather that are dropped from the same height will _____.
Fall at the same rates/hit the ground at the same time
What equation is associated with Newton's Second Law of Motion?
F= ma
Momentum is expressed in units of ____.
kg*m/s
Two balls are dropped from an airplane. Both balls are the same size, but one has a mass ten times greater than the other. The force of air resistance on each ball depends on the ball's speed. Explain whether both balls will reach the same terminal velocity.
To reach terminal velocity, the force of air resistance on the more massive ball must be greater to balance it's larger weight. Air resistance increases as the ball's speed increases, so the more massive ball must be moving faster when air resistance is large enough to balance out it's greater weight.
The greatest velocity reached by a falling object.
Terminal Velocity
A feather will fall through the air more slowly than a brick because of _____.
Air resistance
A little boy pushes a wagon with his dog in it. The mass of the dog is 40 kg and the wagon is 5 kg. The wagon accelerates at 0.85 m/s2 . What force is the boy pulling with?
38.25 N
When two objects collide, the momentum of the pair after the collision is explained by ____.
The Law of the Conservation of Momentum
Marble Picture
Which variable(s) do you use to find the time that the marble will be in the air before it hits the ground?
Height of table (h)
The force that causes an object to move toward the center of a curve.
Centripetal Force
_____ is reached when air resistance and the acceleration due to gravity (aka weight) are equal.
Terminal Velocity
A 68 kg runner exerts a force of 59 N. What is the acceleration of the runner?
0.87 m/s2
A steel ball whose mass is 2.5 kg is rolling at a rate of 3.2 m/s. What is its momentum?
8 kg*m/s
Marble Picture
Which variable(s) do you use to find the landing spot (aka R) of the marble?
Distance the ball travels on table and the horizontal velocity of marble
For every action, there is an equal and opposite reaction.
Newton's Third Law of Motion
An object that is in freefall is ____.
Weightless
Find the mass of a football player who weighs 1250 N.
127.55 kg
A marble is rolling at a velocity of 1.25 m/s with a momentum of 0.08 kg*m/s. What is its mass?
0.064 kg
Marble Picture
Imagine that we increased the height of the ramp by 20 cm, making the ramp a much steeper slope. How would this affect the horizontal velocity of the ball off the end of the table, and how would it affect the drop time of the ball?
Increase, no effect
An object accelerates in the direction of the net force applied to it. F=ma
Newton's Second Law
Object A: mass 5 g, time to fall 2.0 s
Object B: mass 5 g, time to fall 1.0 s
Object C: mass 30 g, time to fall 0.5 s
Object D: mass 35 g, time to fall 1.5 s
Which object above is probably the largest in size? Explain your reasoning.
Object D. It has the greatest mass and falls slowly (2nd slowest) due to having a large Surface Area
3 women push a stalled car. Each woman pushes with a force of 450 N. What is the mass of the car if the car accelerates at 0.85 m/s2 ?
1588.24 kg
A 5.0 kg ham is thrown into a stationary 16 kg shopping cart. At what speed will the cart travel if the ham had an initial speed of 2.4 m/s .
0.57 m/s
Marble Picture
Imagine that we increased the height of the table from the floor. How would this affect the horizontal velocity of the ball off the end of the table and how would it affect the drop time of the ball?
No effect, Increase