Forces and Net Force
a push or pull
What is force?
What variable should be changed when testing how mass affects motion?
What is mass?
When Object A pushes Object B, what does Object B do?
pushes back with an equal-strength force in the opposite direction
What happens when two north magnetic poles meet?
Repel
An attractive interaction between objects with mass
15 N right and 15 N left act on an object. What is the net force?
0 N
Why are repeated trials important?
To determine whether results are consistent/reliable
Why don't action-reaction forces cancel each other?
the forces act on different objects
Which magnetic poles attract? (Two answers)
north and south
What happens to gravity when mass increases but distance stays the same?
gravitational attraction increases
20 N right and 8 N left act on an object. What is the net force and direction?
12 N Right
The same force is applied to a heavy cart and a light cart. Which has the greater change in motion?
the lighter/lower-mass cart
During a collision between a large and small cart, which exerts the greater force?
neither, the interaction forces are equal in strength and opposite in direction
The region around a magnet where magnetic forces can act
What is a magnetic field?
What happens to gravitational attraction when distance increases?
gravitational attraction decreases
A book resting on a table is experiencing ____________ forces.
What is balanced?
What can an unbalanced force change about an object's motion?
speed and/or direction
Why might padding or a crumple zone help protect a passenger during a collision?
it helps protect the passenger during the collision
A magnet produced by electric current/current through a wire
What is an electromagnet?
Explain the difference between mass and weight.
mass is the amount of matter, while weight is the gravitational force acting on an object
If an object is moving at constant speed in a straight line and the net force is zero, what happens to its motion?
What is it continues moving at constant speed in the same direction
Why must scientists control variables when determining how mass affects motion?
so scientists can determine whether mass, rather than another variable, caused the observed change
Explain Newton's Third Law using two colliding carts.
each cart exerts an equal-strength, opposite-direction force on the other cart.
Name two ways an electromagnet can be made stronger.
Examples include increasing the number of wire coils and increasing the electric current.
A student says, “There is no gravity in space because astronauts float.” Explain why the student is incorrect.
Gravity still acts in space and provides the inward force responsible for orbital motion.