Other Physics Answers

A fisherman on a stationary boat jumps off onto a jetty with a velocity of 1.5 ms-1, causing the boat to move backwards.

(i) If the mass of the fisherman and the boat are 65 kg and 450 kg respectively, determine the velocity of the boat. (ii) If the fisherman’s feet are in contact with the jetty for 10 ms, determine the magnitude of the average force exerted on his feet.

A 65.0 kg astronaut is doing a repair in space on the orbiting space station. The astronaut throws a what 2.50 kg toolbox away from him at 3.50 m/s to the space station. (a) With what speed and in direction will he begin to move? (b) How much kinetic energy does the astronaut create by this maneuver?

An 8.00 kg shell at rest explodes in two fragments, with mass ratio of 3:2. If the lighter fragment

gains 90.0 3 of kinetic energy from the explosion, how much kinetic energy does the heavier fragment gain?

A ball is thrown

horizontally with an initial velocity of

30m/s from a height of 2 m. How long will it take to reach the ground? How far will it go?

Determine the electric flux through a Gaussian surface that contains 87 protons and 73 electrons.

A car is stopped at a traffic light. It then travels along a straight road so that its distance

from the light is given by x(t) = bt

2 − ct

3

, where b = 2.40m/s

2

and c = 0.120 m/s

3

.

(a) Calculate the average velocity of the car for the time interval t = 0 to t = 10 seconds.

(b) Calculate the instantaneous velocity of the car at t = 0,t = 5s, and t = 10s.

(c ) How long after starting from rest is the car again at rest?

1. You normally drive on the freeway between Lopez, Quezon and San Pablo, Laguna at an

average speed of 105 km/hr, and the trip takes 2 hours and 20 minutes. On a Friday

afternoon, however, heavy traffic slows you down and you drive the same distance at an

average speed of only 70 km/hr. How much longer does the trip take?

In a charming 19th-century hotel, an old-style elevator is connected to a counterweight by a cable that passes over a rotating disk 1.87m

1.87m in diameter. The elevator is raised and lowered by turning the disk, and the cable does not slip on the rim of the disk but turns with it. Through how many revolutions has the disk turned when it has raised the elevator 3.36m

3.36m between floors?

In a charming 19th-century hotel, an old-style elevator is connected to a counterweight by a cable that passes over a rotating disk 2.9m

2.9m in diameter. The elevator is raised and lowered by turning the disk, and the cable does not slip on the rim of the disk but turns with it. At how many rpm

rpm(revolutions per minute) must the disk turn to raise the elevator at 14.7

14.7 cm/s?

In a charming 19th-century hotel, an old-style elevator is connected to a counterweight by a cable that passes over a rotating disk 1.87m

1.87m in diameter. The elevator is raised and lowered by turning the disk, and the cable does not slip on the rim of the disk but turns with it. Through how many revolutions has the disk turned when it has raised the elevator 3.36m

3.36m between floors?