FBD
Draw a FBD for an object at rest on a table
Check the drawing
Find the Net force on an object that has a mass of 2 Kg and is accelerating at 5 m/s2
10 N
You push a large texbook to the right accross a table. Draw the FBD.
Up: Fn
Down: Fg
Right: Fp
Left: Ff
4 equal forces (up, down, left, right)
Draw a FBD for an elevator that is accelerating upwards.
The upwards force (Force of tension) should be greater than the downwards force of gravity.
A 25 Kg couch is at rest on the floor. What is the Normal Force on that object?
Fn = 245 N
a) What are the two types of friction?
b) Which is always greater?
a) Static and Kinetic
b) Static
A person has a weight of 720N. What is their mass?
73.5 Kg
Draw a FBD for a car that is traveling to the right but slowing to a stop.
Fn (up)
Fg (down)
Fbrake and Ff (left)
What does the slope of a Force vs. Acceleration graph tell you?
m = F/a
You push a desk across the floor to prepare for circle. The desk has a mass of 60Kg and the coeficient of static friction between the desk and the floor is 0.4. What is minimum amount of force you need to apply to make the desk move?
F = 235.2 N
An 3 Kg object is being pushed across the floor at a constant velocity. The coeficient of kinetic friction and the floor is 0.74. What force are you pushing the object with?
21.8 N
Draw a FBD for a 100 Kg cart being pulled by two teams. Team 1 pulls on the right with 250N. The cart accelerates at -2 m/s2. How much force is Team 2 pulling with?
F = -450 N (left)
A cart of mass 5 kg experiences four forces: 70 N upward, 70 N downward, 48 N to the left and 18 N to the right as the cart rolls across the table. What is the resulting acceleration of the cart?
a = -6 m/s2 (left)
Ian is pushing a 25 kg block across the floor. The force of friction between the block and the floor is 50 N. What is the coefficient of friction between the block and the floor?
mu = 0.2
A 100Kg block is placed on a rough, horizontal surface, having a coefficient of static friction μs = 0.8 and a coefficient of kinetic friction μk= 0.5. What is the minimum value of the force F that will cause the block to just begin to move?
F = 784N
Draw a FBD for a 1450 Kg car braking due to friction at -3 m/s2. Label each of the forces. +100 Bonus points if you can find the coeficient of friction between the tires and the road.
Fn = 14,210 N up
Fg = 14,210 N down
Ffk = 4350 N left
mu = 0.31
Draw velocity vs time graph for the following scenario:
An object that has a positive net force acting on it for 10s. After 10s the net force suddenly becomes 0N.
Positive slope until 10s then 0 slope.
A boeing 747 has a mass of 40,000 Kg and there is a coefficient of friction between the runway and the tires of 0.60. The plane can generate a maximum thrust to force of 315,000N as it takes off. What is the acceleration of the plane?
a = 1.995 m/s2
A football player hits a 85 kg training dummy with a force applied parallel to the ground. The sled accelerates at 4 m/s2 and the force of kinetic friction is 90 N.
What force did the football player apply to the dummy?
F = 430 N