Force
A push or pull is called a ___________.
Force
If you increase the mass on an object, its acceleration _________.
a) increases
b) decreases
c) stays the same
d) stops
b) decreases
projectile
Newton's third law states that for every reaction, there is a(n) ___________________.
equal but opposite reaction
What is a satellite?
Any object that travels around another object in space.
What causes an object to start moving?
a) inertia
b) balanced forces
c) mass
d) unbalanced forces
d) unbalanced forces
(it is equal to 1 kg x 1 m/s2)
newton
A fluid friction that objects falling through the air experience is called air ______________.
resistance
true or false?
Forces work in pairs.
true
The force that causes an object to move in a circle is a _______ force.
a) momentum
b) centrifugal
c) centripetal
d) equal but opposite
c) centripetal
Newton's _____ law states that an object at rest will remain at rest and an object moving (at constant velocity) will continue moving unless acted upon by an __________force.
a) 2nd law, unbalanced
b) 1st law, unbalanced
c) 2nd law, balanced
d) 1st law, balanced
b) 1st law, unbalanced
What is the equation for force? ( it is the relationship described in Newton's 2nd law)
f = ?
force = mass x acceleration
f = m x a
The strength of the force of friction depends on how much the surfaces are pushed together and __________________.
The types of surfaces involved (ex: rough vs smooth surfaces)
The momentum of an object is the product of its mass and its _______: Momentum = mass x ?
a) velocity
b) weight
c) acceleration
d) speed
a) velocity
momentum = mass x velocity
*remember that velocity is speed with a direction!
Which of Newton's laws can explain how a rocket is launched into space?
Newton's third law. The gases from the rocket have a downward force equal but opposite to the thrust upward.
The SI unit of mass is ____
kilogram (kg)
How much force is needed to accelerate a 25 kg ball at 2 m/s2?
f = 50 newtons
When the only force acting on an object is gravity, the object is in ___________.
a) motion
b) free fall
c) terminal velocity
d) universal gravitation
b) free fall
What is the momentum of a 20 kg dog running at a speed of 8 m/s2?
160 kg * m/s
Why do satellites travel around the Earth, but don't hit it?
Satellites in orbit around the Earth fall toward the Earth (due to gravity) but travel around it because the Earth is curved.
An object resisting a change in motion is called ____.
inertia
If you increase the force on an object, its acceleration __________.
a) decreases
b) stays the same
c) also increases
d) stops
c) also increases
All objects in free fall accelerate at ____ m/s2
9.8 m/s2
Could an elephant have the same momentum as a golf ball? WHY or WHY NOT
Yes, since momentum = mass x velocity, a very slow moving elephant could have the same momentum as a very fast moving golf ball.
What is the centripetal force acting on the moon?
gravity