Phys 1L03 Tutorial session Set 6
Sixth series: Questions on Newton’s Laws
1. A mother of mass 50 kg and her daughter of mass 25 kg are ice-skating. They face each other, and
the mother pushes on the daughter such that the daughter’s acceleration is 2 m/s . 2
a. What is the force exerted by the mother on the daughter?
b. What is the force exerted by the daughter on the mother?
c. What is the mother’s acceleration?
2. Suppose that the coefficient of kinetic friction of the rubber of a car tire and the street is ▯ k 0.8 .
What is the deceleration of a car on a flat street if the driver brakes sharply, so all the wheels are
locked and skidding?
3. A force F = 180 N pulls on a crate at a 60 on a rough surface. The weight of the crate is 296 N and the
friction force between the crate and the surface is 90 N. What state of motion may the crate be?
4. A man pushes a heavy crate. His push makes an angle of 30 with o
the horizontal, as shown. The mass of the crate is 60 kg, and the
coefficient of sliding friction is ▯k▯ 0.50 . What force must he exert
to keep the crate moving at uniform velocity?
What force does he have to apply if he pushes upward instead of
5. A ship is launched toward the water on a slipway making an angle of 5 with the horizontal
direction. The coefficient of kinetic friction between the
bottom of ship and the slipway is ▯ ▯ 0.08 .
a. What is the acceleration of the ship along the
b. What is the speed of the ship after accelerating
from rest through a distance of 120 m down the
slipway to the water?
6. Two masses m 1 and m 2re connected over a light, frictionless pulley by a light rope as shown. m is 2
hanging and m is1moving on a frictionless ramp. The angle of the inclined is ▯ =15 . If the accel