Forces
A 20 kg crate is pushed with a force of 100 N, but the frictional force is 60 N. What is the net force acting on the crate?
40 N
What metal/material is typically a magnetic material?
iron (or steel)
How could you increase the strength of an electromagnet?
add more coils, coil tighter, overlap wires, increase power source (battery)
Which law is this: An object at rest stays at rest, and an object in motion continues in motion with the same speed and in the same direction unless acted upon by a net external force.
Newton's 1st Law
Which two subatomic particles are found in the nucleus of an atom and account for almost all of the atom's mass?
Protons and neutrons
A box weighing 50 kg is pushed across a floor with a force of 200 N. If the frictional force opposing the motion is 150 N, what is the net force acting on the box?
50 N
What happens to the strength of a magnet as you move further away from it?
It decreases
What is the role of a magnetic field in an electric generator?
It helps to create electricity through electromagnetic induction
Which of newton's laws states that force is equal to mass times acceleration?
Newton's 2nd Law
What is the charge of an electron?
negative
A person pushes a shopping cart with a force of 100 N to the right, while friction acts to the left with a force of 40 N. What is the net force on the cart?
60 N to the right
If you break a magnet in half, what will happen to the two pieces?
Each piece will become a smaller magnet with its own north and south poles
What two types of magnet are commonly used in electric motors?
Permanent magnet and electromagnet
Which law states: For every action, there is an equal and opposite reaction. This means that forces always occur in pairs
Newton's 3rd Law
Atomic number is based off of the number of ___________ in an atom
protons
A cyclist is pedaling uphill and exerts a force of 250 N. If the frictional force acting against them is 100 N, what is the net force acting on the cyclist?
150 N uphill
What happens to the magnetic field of an electromagnet when the electric current is turned off?
It disappears
How does electromagnetic force differ from static electricity?
Static electricity is a stationary charge, while electromagnetic force involves moving charges
Which of the following properties is a measure of an object's inertia?
a) volume
b) density
c) weight
d) mass
Why are atoms generally neutral in charge?
A car is parked on a hill. What forces are acting on the car?
Gravity and normal force
As distance between magnets decreases, what happens to magnetic force?
It increases
What is electromagnetic induction?
The generation of an electric current by a changing magnetic field
A car of mass m is traveling at 20 m/s. A truck of mass 2m is traveling at 10 m/s. Which object is easier to stop?
They are equally easy to stop because their momentums are equal. (f=m x a)
How do you calculate atomic mass?
Add the number of protons and neutrons