Do balanced or unbalanced forces on an object cause it to move?
Unbalanced forces cause objects to move.
100
Do you add or subtract forces that are acting in opposite directions?
Subtract forces acting in opposite directions.
100
Which law states that the greater the force, the greater the acceleration, and the greater the mass, the lesser the acceleration of an object?
The 2nd law - F=ma
100
What net force is required to accelerate a car at a rate of 2 m/s^2 if the car has a mass of 3,000 kg?
F = ma = (3,000 kg)(2 m/s^2) = 6,000 N
100
The 3rd law of motion states that for every action there is a(n) __________ and __________ reaction.
1) equal
2) opposite
200
All forces have two things. What are they?
All forces have a magnitude and a direction.
200
Two eighth grade football players pushed against a tackle sled with their coach standing on it. The first put 26 N of force into the sled, and the second player pushed with 31 N. Ignoring friction, what is the net force applied to the sled?
Because the forces are acting in the same direction, they are added together - Net Force = 26 N + 31 N = 57 N
200
A boy is sledding down a steep hill after a heavy snowfall. The sled catches a large rock covered by the snow, stopping it suddenly, but the boy flies forward off of the sled. Which law explains why this happened to the boy?
The 1st law of motion - the law of inertia. A body in motion tends to stay in motion unless an outside force acts on it.
200
Sally has a car that accelerates at 5 m/s^2. If the car has a mass of 1000 kg, how much force does the car produce?
F = ma = (1,000 kg)(5 m/s^2) = 5,000N
200
According to the 3rd law of motion, when a table is pushed into a wall, the wall pushes back against the table with ______________ (a greater, a lesser, or the same) amount of force.
The wall pushes back against the table with the same amount of force.
300
If a girl leans against the wall while talking to her friend, putting 12 N of force into the wall, the wall pushes back against her with how much force?
The wall pushes back with the same amount of force - 12 N.
3rd Law - For every action there is an Equal and Opposite reaction.
300
If a car produces 12,000 N of force going east down the highway, and it encounters 750 N of air resistance, what is the net force of the car?
Net Force = 12,000 N - 750 N = 11,250 N
300
When Oscar stepped off a skateboard, he went forward and the skateboard rolled backwards. Which law explains this experience?
The 3rd law of motion, which states that for every action there is an equal and opposite reaction.
When Oscar pushed forward on the board, the board moved in the opposite direction with an equal amount of force.
300
What is the mass of a truck if it produces a force of 14,000 N while accelerating at a rate of 5 m/s^2?
m = F/a = (14,000 N) / (5 m/s^2) = 2,800 kg
300
What are the units of Force, Mass, and Acceleration?
Force - N
Mass - kg
Acceleration - m/s^2
400
What is the force of attraction that acts between any two objects with mass?
The force is gravity.
400
The sum of all forces acting on an object is called the __________________?
Net Force
400
When Jane drives to work, she always places her pocketbook on the passenger’s seat. By the time she
gets to work, her pocketbook has fallen on the floor in front of the passenger seat. One day, she asks
you to explain why this happens in terms of physical science. What do you say?
The pocketbook's inertia carried it forward off of the seat when Jane put on the brakes.
400
An 80 kg basketball player jumps, accelerating himself upwards at 16 m/s2. What force do his shoes exert on the ground during this acceleration?
F = ma = (80 kg)(16 m/s^2) = 1280 N
400
Sophia, whose mass is 52 kg, experienced a net force of 1800 N at the bottom of a roller coaster loop during her school's physics field trip to the local amusement park. Determine Sophia's acceleration at this location.
A = F/m = (1800 N) / (52 kg) = 34.6 m/s^2
500
____________ is the force of gravity on an objects mass.
Weight
500
When the net force is zero newtons, then the forces are _____________.
balanced
500
Annie's mother asked her help to push a heavy couch to another room in the house. If they decreased the mass of the couch by taking the pillows and cushions off of the couch before they moved it, what effect would it have on the acceleration of the couch when they moved it?
The acceleration of the couch would become greater.
500
A mother is pushing a stroller that has a mass of 26 kg. If she applies a force of 13 N, what is the acceleration of the stroller?
A = F/m = (13 N) / (26 kg) = 1 / 2 m/s^2 = 0.5 m/s^2
500
Which law of motion explains the importance of wearing a seat belt when riding in a vehicle?