Inclined Planes
Systems and Newtons Laws
Free body diagrams and Universal Gravitation
Friction
Basic Forces
100
A 20.0 kg mass is placed on a 60 degree incline. If the coefficient of friction is 0.35, what is the total Net Force produced?
136 N
100
If an object is in uniform motion, it will tend to stay in motion unless an external force is applied to it. True or False
True
100
You are in an elevator on the main floor of a building and need to get to the second floor. While in the elevator, what forces are acting on you?
Fn and Fg
100
Is ice frictionless?
NO. No surface no matter how smooth it seems is frictionless
100
A 1200 kg car comes to a stop from a speed of 25 m/s in 6.5 s. What braking force was required?
4.6 x 10^3 N
200
An 83kg skier is traveling down the slope which is 60° from the horizontal; the coefficient of kinetic friction between the snow and their waxed skis is 0.15. Determine the acceleration of the skier down the slope.
7.8 m/s2
200
Say a box that weighs 20lbs is pushed East at 3.45m/s2 what is the net force?
7.03N
200
(see board) Fill in the blanks. Which force is missing in the diagram?
Force of Friction
200
A 20.0 kg mass is pulled by along a surface by a horizontal force of 100 N. Friction is 20.0 N. What is the acceleration of the mass??
4m/s2
200
What is the initial velocity of a 2.2 kg object that experiences a net force of 2.50 N for 8.0 s giving it a final velocity of 70 m/s?
61 m/s
300
A 10.0 kg mass is allowed to accelerate down a 20 m frictionless inclined plane. What is the block's final velocity if the incline is at an angle of 45 degrees?
16.7 m/s
300
Explain what the term inertia means.
The tendency of a body to maintain its state of rest or uniform motion unless acted upon by an external force.
300

(see board) You pull box B across a floor with no friction. What forces are acting on box A?

Ft, Fg, Fn

300
A man is pushing a box of bricks across a floor with a force of 120N. The mass of the man is 80kg and the mass of the box is 60kg. The Force friction is 12N. What is the coefficient of friction?
.02
300
A car of mass 1.5 x 103 kg is being driven at 20 m/s. The driver sees a massive hole 100 m ahead. What is the minimum frictional force required to stop the car in time?
3000 N
400
A 5.0 kg mass is on an incline which makes an angle of 50o with the horizontal. The incline has a coefficient of friction of 0.10. If the mass is released from rest, at what rate does it accelerate?
6.88 m/s2
400
A 150 N force is applied to a system of masses. If mass A has a 50 N frictional force and mass B has a 70N frictional force, find the acceleration of the system?
0.60 m/s2
400
What is the force exerted by Big Ben on the Empire State building? Assume that Big Ben has a mass of 108 kilograms and the Empire State building 109 kilograms. The distance between them is about 5000 kilometers and Big Ben is due east of the Empire State building.
2.67 x 10 -7 N
400
A 15.0 kg block is pulled by a horizontal force of 30.0 N along a rough horizontal surface at constant velocity. What is the coefficient of friction?
0.2
400
A child's wagon experiences a frictional force of 73 N whenever it is in motion, regardless of the load it is carrying. An applied horizontal force of 128 N causes the wagon to accelerate at 5.0 m/s2. The same applied force, with a child on the wagon, causes it to accelerate at 1.0 m/s2. What is the mass of the child?
44 kg
500
A 360 N force is applied down the incline to a 150 N box which experiences a force of friction of 75.0 N. If the angle of the incline is 55 degrees, what is the net acceleration of the box?
26.7 m/s2
500
In this system there are two masses; one is resting on a flat table (3 kg) and the second mass is hanging off the table (1 kg). What is the acceleration and for the pulley if the coefficient of friction is 0.19?
1.1m/s2
500
What is the gravitational force that the sun exerts on the earth? The earth on the sun? In what direction do these act? (Mass of Earth = 5.98×10^24 and Mass of Sun = 1.99×10^30 and the earth-sun distance is 150×10^9 meters).
3.53 x 10^22
500
A person is pushing a 49 kg box so that the applied force of 950 N is at an angle of 15º to the parallel. The coefficient of kinetic friction is 0.37. Determine the acceleration of the car.
12 m/s
500
A jet accelerates vertically up at 8.5 m/s2. What force does the exhaust gas exert on the 4400 kg jet?
8.1 x 10^4 N
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