Normal Force
What is are Newton's 3 laws of motion
2.) F = ma
3.) For every action there is an equal but opposite reaction
What is the formula to solve for firction?
Ff = muFN
What is the tension formula for a hanging mass at rest?
T = mg
What is the force components of an object at an incline/angle?
Fgparallel = Fgsintheta
An object moves foward with a constant velocity. What additional information do we need to know to determine the force acting upon the object?
A.) The mass of the object
B.) The velocity of the object
C.) The distance the object travels
D.) Time of the object in motion
E.) Force is 0N
E
A 5 kg box rests on a table. Draw the free-body diagram for the box.
Check FBD (N = mg)
What is the difference between static friction and kinetic friction?
Kinetic Friction: The amount of friction when an object moves against a surface.
A 500 kg box is being held up by a crane. What is the force of tension in the crane?
4900 N
If an object is at rest, can you conclude that there are no forces acting upon it?
No, even if an object is at rest, forces are still acting upon the object to keep at equilibrium in rest.
Two dogs are pulling on a bone. One pulls with 32N of force to the right and one pulls with 35N to the left. What is net force of the bone?
3N to the left (-3N)
A 7000g box is pushed to the right with 10 N of force. The force of friction that acts against the motion is 4.5 N. What is the kinetic coefficient friction and acceleration of the object?
muk=0.065
a=0.78 m/s2
A 3 kg box is being held up by a massless cord. If the tension decreases and it starts accelerating downward with 1 m/s2 what is the tension in the rope?
26.4 N
A dog of 100kg sits on a sled while two friends drag the dog across the snow with ropes. If the coefficients of friction are mus =0.60 and muk = 0.25, and the angle between the ropes is 20 degrees, how hard much each friend pull to keep the dog moving at a constant velocity?
T= 245N/2cos10
T = 124N
Louis pushes a block with 31N of force. He observes that it has a constant linear acceleration of 2.1 m/s2 . What is the mass of the block?
A.) 12.1kg
B.) 14.76kg
C.) 1.41kg
D.) 15.12kg
E.) 33.22kg
B
A 2.5 kg box slides on a frictionless floor with an acceleration of 4 m/s2. What is the force used to push the box?
10 N
A skier with a mass of 62kg os sliding down a snowy slope of angle 35 degrees. What is the force of friction if the coefficient of kinetic friction is 0.09?
Ff = 45N
A box weighing 45kg hangs from a rope that is attached to the ceiling of an elevator. If the tension in the rope is measured to be 531 Newtons, what direction is the elevator accelerating in and at what rate is it accelerating?
2 m/s2
An object is held up from two ropes, each with a tension of 5 Newtons at an angle of 60 degrees. What is the mass of an object and what angle would the ropes have to be if the tension was 10N.
m=0.88kg
26 degrees
A mosquito collides head-on with a car traveling 60mph. What is the magnitude of the mosquito's acceleration?
A.) Larger than the acceleration of the car
B.) Smaller than the acceleration of the car
C.) Equal to the acceleration of the car
A
A skier with a mass of 82000g slides down a snowy slope at an angle of 42 degrees. Find the coefficient of kinetic friction for the skier if the friction is known to be 51N.
muk = 0.085
A box weighing 20 kg is left on a ramp. If the coefficient of friction between the box and the ramp is 0.4 (static), what is the maximum angle the ramp can have for the box to not slip at all?
21.8 degrees
Three blocks are connected by ropes from a massless, frictionless pulley system. The block hanging from the left is 1kg, the block on the table is 2kg and the block hanging on the right of the table is 3kg. The coefficients of friction between the block and table is mus = 0.60 and muk = 0.3. What is the acceleration of the 2kg block?
a = 2.29m/s2
A mosquito collides head-on with a car traveling 60mph. What is the force of the mosquito acting upon the car?
A.) Larger force than the car
B.) Smaller force than the car
C.) Equal force to the car
B