Mechanics | Relativity Answers

An electron traveling at relativistic speed moves perpendicular to a magnetic field of 0.20 𝑇. Its path is circular, with a radius of 15 𝑚. Find: (a) the momentum, (b) the speed, and (c) the kinetic energy of the electron. Recall that, in nonrelativistic situations, the magnetic force 𝑞𝑣𝐵 furnishes the centripetal force 𝑚𝑣 2⁄𝑟. Thus, since 𝑝 = 𝑚𝑣 it follows that 𝑝 = 𝑞𝐵𝑟 and this relation holds even when relativistic effects are important. 

What must be the velocity of a spacecraft if 1 ℎ on its clock is to correspond to 1 ℎ + 1 𝑠 on a clock on

the earth?

(i) Compute the value of 𝛾 for a particle traveling at half the speed of light. Give your answer

to three significant figures.

(ii) Determine the energy required to give an electron a speed of 0.90 that of light, starting from

rest.

What is gravitational accelearation.

What is friction force?

1.     What happens to the speed, does it slow down as different objects are added and the applied force is different?  Why do you think this happens?

2.     If forces are balanced, then the net force is zero. Is there a sum of forces, or net force here?

1. A box of mass 5 kg is accelerated from rest across a floor at a rate of 2 m/s2  for 7 s. Find the net work done on the box.

A car running at a speed of 72 km/h is to be stopped in exactly 10 seconds. Find the uniform deceleration needed.

A patient transport vehicle is running at a speed of 80 m/s. It is the decelerated at the rate of 10m/s. When will it stop?

A Carnot heat engine receives heat at T1 and rejects the waste heat to the environment at T2. The

entire work output of the heat engine is used to drive a Carnot refrigerator that removes heat

from the cooled space at 258 K at a rate of 400 kJ/min and rejects it to the same environment at

T2. Determine

(a) The rate of heat supplied to the heat engine and

(b) The total rate of heat rejection to the environment.