Download 332 Physics – Unit 2 Review (Newton`s Laws, 1D forces) DON`T

332 Physics – Unit 2 Review (Newton’s Laws, 1D forces)
DON’T FORGET CONCEPTS (1ST Law, 3rd Law, falling through air) in addition to problems
1) An African elephant can possess a mass of 6000kg. Determine the weight of an African elephant in
Newtons.
2) According to the National Center for Health Statistics, the average mass of an adult American male is
86kg.
a) Determine the mass
b) Determine the weight of this person where the acceleration due to gravity is one-sixth that of the
Earth.
3) The Top Thrill Dragster stratacoaster at Cedar Point Amusement Park in Ohio uses a hydraulic
launching system to accelerate riders from 0 to 54 m/s (120 mi/hr) in 3.8 seconds. Determine the net
force required to accelerate an 86-kg man.
4) A girl pulls a wagon exerting a 52N forward force on the wagon. There is a 24N friction force on the
wagon. The wagon has a weight of 304N.
a) Construct a force diagram for the wagon.
b) Determine the normal force.
c) Determine the acceleration of the wagon.
5) A baseball player slides into second base. As he hits the dirt on his head first dive, his 73.2 kg body
encounters 249N of friction force.
a) Construct a force diagram
b) Determine the acceleration.
c) Determine how far he would he slide if he hits the dirt at 8.5m/s
6) During a skydiving jump, a skydiver’s 82.5-kg body experiences 118 N of air resistance.
a) Draw force diagram
b) Determine acceleration of skydiver at this instant in time.
7)) You are trying to move a piano. You exert a sudden forward force of 524N to budge the piano from rest.
a) Find the coefficient of static friction between piano and floor for the 158-kg piano.
b) If it takes 400N to move it at constant velocity, determine the coefficient of kinetic friction.
8) A rope is used to pull a 2.89-kg bucket of water out of a deep well.
a) Draw force diagram.
b) Determine the acceleration of the bucket when the tension in the rope is 30.2N.
c) If starting from rest, calculate speed the bucket have after experiencing this force for 2.16 seconds.
ANSWERS: 1) 58,800N 2) 86kg, 140N 3) 1222N 4) 304N, 0.90 m/s2 5) -3.40 m/s2 , 10.6m 6) -8.37 m/s2
7) 0.34, 0.26 8) 0.65 m/s2 , 1.4 m/s 9) 5.79N 10) 230N 11) 8.3 m/s2 12) 0.0197N, 0.012 13) 5020N, 3388N, 4000N 14)
21.6m 15) 504N 16) 2.7m/s2 17) 2.45N, 12.9 N 18) -0.98m/s2 , 441N, speeding up downwards
9) A 0.104-kg model rocket accelerates at 45.9 m/s/s on takeoff. Determine the upward thrust force
experienced by the rocket. Draw a force diagram.
10) Barry is attempting to drag his 32.6-kg Golden Retriever across the wooden floor by applying a
horizontal force. The coefficient of kinetic friction between the dog and the floor is 0.72. Determine the
force necessary to move the dog with a constant speed of 0.95m/s. Draw a force diagram.
11) The coefficient of kinetic friction between the wheels of a car and dry pavement is 0.85. Determine
the acceleration which the 1300-kg Coupe experiences while skidding to a stop. Draw a force diagram.
12) A hockey puck (0.162kg) decelerates from 10.5 m/s to 8.8 m/s in 14 seconds.
a) Draw force diagram
b) Determine the force of friction experienced by the puck.
c) Determine the coefficient of friction between the ice and the puck.
13) An elevator is being pulled by a cable. If the elevator weighs 4000N, find the tension in the cable if
a) the elevator accelerates upwards at 2.5m/s2.
b) the elevator accelerates downwards at 1.5m/s2
c) the elevator rises at constant speed.
14) A 1000kg boat moves across the water with a force of 2100N while experiencing a resistive force of
1800N. If it starts from rest, how far will it move in 12s?
15) The parachute on a dragster opens at the end of a quarter-mile run when it is moving at 35m/s. What
retarding force must the parachute experience to stop the dragster in a distance of 1100m if the dragster
weighs 8820N?
16) A balloon (m=400kg) is acted by an upward force of 5000N. Ignore friction. Determine the acceleration of the
balloon.
17) A student pushes horizontally on a textbook of mass 0.250 kg and holds it
stationary against the classroom wall.
a) Draw a force diagram for the textbook
b) Determine the friction force that holds the text in place.
c) The coefficient of static friction between book and surface is 0.190. Determine
the minimum force needed to hold the textbook in place.
18) An elevator cable has a tension of 9,700N. The elevator has a mass of 1100kg.
a) Draw a force diagram
b) Calculate the acceleration of the elevator.
c) If a 50kg person is inside, determine the scale reading on them during the acceleration.
d) Describe motion of elevator for the above condition to be true.
ANSWERS: 1) 58,800N 2) 86kg, 140N 3) 1222N 4) 304N, 0.90 m/s2 5) -3.40 m/s2 , 10.6m 6) -8.37 m/s2
7) 0.34, 0.26 8) 0.65 m/s2 , 1.4 m/s 9) 5.79N 10) 230N 11) 8.3 m/s2 12) 0.0197N, 0.012 13) 5020N, 3388N, 4000N 14)
21.6m 15) 504N 16) 2.7m/s2 17) 2.45N, 12.9 N 18) -0.98m/s2 , 441N, speeding up downwards