Problem 1: Mary pushes on a 50 kg box of books. The box accelerates at a rate of
ID: 1883428 • Letter: P
Question
Problem 1:
Mary pushes on a 50 kg box of books. The box accelerates at a rate of 2.5 m/s
(a) What is the magnitude of the force Mary exerts on the box of books?
(b) Several books are removed from the box, such that the box’s mass is now 20 kg. If Mary pushes with the same force from part (a), what is the new acceleration of the box?
Problem 2:
A 2,000 kg car is traveling with an initial speed of 70 km/hr. What magnitude of force will bring the car to a stop in 10 s?
Problem 3:
Alice and Ben are standing in the middle of an ice rink without any ice skates. To reach the edge of the rink, they decide that Alice will push off of Ben, causing them both to slide along the ice in opposite directions. Alice has a mass of 60 kg, and Ben has a mass of 80 kg. If Alice pushes on Ben with a force of 150 N, what is the acceleration that they each feel?
Problem 4:
A 5 kg block slides down a frictionless slope. Calculate the angle of the slope and the magnitude
of the block’s normal force if the block accelerates at a rate of 4 m/s
Problem 5:
A 2,000 kg car drives around circular track of radius 200 m. The car maintains a constant
speed of 12 m/s.
(a) What is the centripetal force on the car?
(b) What is the period of the car’s circular motion?
Problem 6:
A child on a merry-go-round experiences a centripetal force of 12 N.
(a) If the child weighs 240 N, what is the centripetal acceleration of the merry-go-round?
(b) If the child moves at a speed of 3 m/s, how far is she from the center?
Problem 8:
Calculate the weight of a 1.5 kg textbook on the surface of the Earth as well as the surface of the Moon.
Problem 9:
The Moon is 384,000 km from the Earth and takes 27 days to make a complete revolution about
the Earth. What is the force exerted on the Moon by the Earth? The mass of the Moon is 7.36 x 10^22kg.
Explanation / Answer
Problem 1)
Given,
Mass, m = 50 kg
Acceleration, a = 2.5 m/s^2
Force, F = m x a = 50 x 2.5 = 125 N
B)
Force, F = 20 x 2.5 = 50 N
Problem 2)
Mass, m = 2000 kg
Initial velocity, u = 70 km/h = 19.44 m/s
Time, t = 10 sec
V = u + at
0 = 19.44 + a x 10
Acceleration, a = - 1.94 m/s^2
Force, F = 2000 x 1.94 = 3888.89 N
According to Chegg guidelines I can answer one question (though I did 2 questions) at a time so please post other questions separately....