Newton's 1st Law
What is Newton's 1st Law?
Objects at rest will stay at rest until acted on by a force.
What is Newton's 2nd Law?
Force = mass times acceleration
F = m x a
What is Newton's 3rd Law?
Every action has an equal and opposite reaction
What is gravity?
The attractive forces between two objects
13.3 hours
What is the net force on an object if two people are pushing 50 N from the left and one person is pushing 50 N from the right?
The net force acting on the object is 50 N to the right.
Which two factors affect the rate of acceleration?
Force and Mass
(Think of the formula!)
If you push on a wall with a force of 200 N, what force will be exerted by the wall?
200 N
What is the constant for gravity?
9.8 m/s2
A professional baseball player can pitch a baseball with a velocity of 44.7 m/s towards home plate. If a baseball weighs 1.4 N, how much momentum does it have when it hits the catcher's mitt?
6.4 kg x m/s
1. Fg = m x g
2. p = m x v
Which type of friction is between two objects that are NOT moving?
Static friction
A dancer lifts his partner above his head with an acceleration of 2.5 m/s2. The dancer exerts a force of 200 N. What is the mass of the partner?
80 kg
What forces are acting upon you AND the trampoline when you jump on a trampoline?
When you jump on a trampoline you exert a downward force on the trampoline.
The trampoline exerts an equal force upward, sending you into the air.
If you drop a moose and a muffin at the same time and there is NO AIR, what will happen?
A 3 kg model airplane is traveling at a speed of 33 m/s. The operator then increases the speed up to 45 m/s in 2 seconds. How much force did the engine need in order to make this change?
18 N
1. a = vf - vi / t
2. F = m x a
Which has more inertia and why -- a bowling ball or a basketball?
A bowling ball, more mass = more inertia
If an object falling at 9.8 m/s2 has a mass of 50 kg, what force will it hit the ground with?
490 N
Which has more momentum? A semi-truck or a golf cart? Why does it have more momentum?
Bonus 100 points: Why do you not merge right in front of a semi?
The semi-truck. It has more momentum due to it having more mass than a golf cart.
Bonus: Semi-trucks cannot slow down quickly due to having so much momentum, so if you merge right in front of it and it has to slow down quickly to avoid hitting you, it will hit you or others.
Why would a larger planet have a higher gravitational force than a smaller planet?
The more mass an object has, the more gravitational force it has. (Think of the Sun vs Earth)
In a collision, a 15 kg object moving with a velocity of 3 m/s transfers all of its momentum to a 5 kg object. What would be the velocity of the 5 kg object after the collision?
9 m/s
1. p = mv
2. v = p/m
What is inertia?
How difficult it is to change an object's motion
If a 70-kg swimmer pushed off a pool wall with a force of 250 N, at what rate will the swimmer accelerate from the wall?
3.57 m/s2
What forces will be applied if you push a rolling cart down a hill?
Hint: there are 4 forces
Gravity, Air resistance, Rolling friction, AND the force that you applied on the rolling cart pushing back on you.
What is the friction between air and a falling object?
Air resistance
A dog has a mass of 3 kg. What is its weight?
29.4 N
1. Fg = m x g