MALAWI UNIVERSITY OF SCIENCE AND TECHNOLOGY
PHYS-111 Tutorial: Chapter 6
1. A 90.0-kg fullback running east with a speed of 5.00 m/s is tackled by a 95.0-kg
opponent running north with a speed of 3.00 m/s. If the collision is perfectly inelastic,
calculate the speed and direction of the players just after the tackle.
2. A billiard ball moving at 5.00 m/s strikes a stationary ball of the same mass. After the
collision, the first ball moves, at 4.33 m/s, at an angle of 30.0° with respect to the
original line of motion. Assuming an elastic collision (and ignoring friction and rotational
motion), find the struck ball’s velocity after the collision.
3. Two shuffleboard disks of equal mass, one orange and the other yellow, are involved in
an elastic, glancing collision. The yellow disk is initially at rest and is struck by the orange
disk moving with a speed of 5.00 m/s. After the collision, the orange disk moves along a
direction that makes an angle of 37.0° with its initial direction of motion. The velocities
of the two disks are perpendicular after the collision. Determine the final speed of each
disk.
4. In a crash test, a car of mass 1500 kg collides with a wall and rebounds. The initial and
final velocities of the car are 𝑣𝑖 = 15.0 m/s and 𝑣𝑓 = 2.60 m/s, respectively. If the
collision lasts for 0.150 s, find
a. The impulse delivered to the car due to the collision
b. The size and direction of the average force exerted on the car.
5. A Mercedes Benz with mass 1.8 × 103 kg is traveling east bound at +15.0 m/s, while a
compact car with mass 9.00 × 102 kg is traveling west bound at -15.0 m/s. The cars collide
head-on, becoming entangled. Find;
a. The speed of the entangled cars after the collision.
b. The change in the velocity of each car.
c. The change in the kinetic energy of the system consisting of both cars.
6. A car of mass 1.50 × 103 kg travelling west with the velocity of 25 m/s collides with a van
of mass 2.50 × 103 kg travelling south with an initial velocity of 20 m/s. Assuming they
underwent a perfectly inelastic collision, find the final velocity of the wreckage.
7. Using relevant formulae, explain how the seat belt and airbag protect a passenger during
an accident.