Forces
What is a force?
A push or a pull
What is energy of motion called?
Kinetic energy
Why does a bike slow down when you stop pedaling?
Friction
Name TWO ways motion can change.
speed up, slow down, stop, change direction
What force pulls objects towards earth?
Gravity
What is stored energy called?
Potential energy
A book is sitting still on a desk. Are forces balanced or unbalanced?
Balanced
What happens when unbalanced forces act on an object?
Motion changes
What force slows objects down when they rub together?
Friction
At the top of the roller coaster, what type of energy is the greatest?
Potential energy
Why does an apple fall from a tree?
Gravity
Compare kinetic and potential energy
kinetic is moving and potential is stored.
If forces are balanced, what happens to motion?
No change (stay still or at a constant speed)
As a roller coaster goes down, what happens to energy?
potential to kinetic
A student pushes a box and it doesn't move. Why?
Forces are balanced. The friction matches the push. (pushing it on carpet)
Explain how friction and gravity both affect motion.
Gravity pulls the object' down and friction slows the movement.
Give an example of unbalanced forces and explain what happens.
Kicking a ball. Motion changes because the force is not balanced. Force on one side of the ball but not the other.
Explain how BOTH kinetic and potential energy are involved when throwing a ball into the air.
Kinetic as it goes up.
Potential at the top.
Kinetic as it falls to the ground again.
Explain why a rolling ball eventually stops using force and energy.
Friction slows the motion and kinetic energy decreases.
A skateboarder starts at the top of the ramp, rolls down, and stops at the bottom. Explain what happens using FORCES and ENERGY
Gravity pulls them down (unbalanced force). kinetic energy increases while moving, friction slows them at the bottom until they stop.