Mechanics | Relativity Answers

a wheel has a moment of inertia of 2.0 kgm2 about its axis of rotation. It is rotating with an angular speed of 50rpm. Calculate the torque that can stop the wheel in one minute. Also calculate work done by the torque in this time.

A spaceship is receding from the earth at a speed of 0.3c. A light on the spaceship
emits light of wavelength 4500 Å(angstrom) which appears blue to a passenger on the
spaceship. What colour would the light appear to a person on earth?

A hot air balloon is rising straight up at a constant speed of 7.0 m/s. When the balloon is 12.0m above the ground, a gun fires a pellet straight up from ground level with an initial speed of 30.0m/s. Along the paths of the balloon and the pellet, there are 2 places where each of them has the same altitude at the same time. How far above the ground are these 2 places?

A particle starts moving along a straight line with initial velocity of
25m/s, from O under a uniform acceleration of -2.5 m/s2. Deterime
(i) Velocity, displacement and the distance travelled at t= 5
sec
(ii) How long the particle moves in the same direction? What
is its velocity, displacement and the distance covered
then?
(iii) The instantaneous velocity , displacement and the distance
covered at t=15 sec
(iv) The time required to come back to O, velocity,
displacement and distance covered then
(v) Instantaneous velocity, , displacement and distance
covered at t=25 sec

The rectilinear motion of a particle is defined by the displacement-time
equation as x=x0+v0t+(1/2)at2
. Find the displacement and velocity at
time t=2s while x0=250mm, v0=125mm/s and a=0.5mm/s2

a man goes x to place y and return to place x on his motor bike. the distance between place x and y is 180 km and takes 4 hours 30 minutes to complete his journey, find his average speed and velocity in km/h

One end of a cord is fixed and a small 0.500-kg object is attached to the other end, where it swings in a section of a vertical circle of radius 2.00 m as shown in the Figure. When θ = 20.0°, the speed of the object is 8.00 m/s. At this instant, find (a) the tension in the string, (b) the tangential and radial components of acceleration, and (c) the total acceleration.

You're riding a unicorn at 25m/s and come to a uniform stop at a red light 20m away. What's your acceleration ?

Object thrown up Vi = 110 m/s,
sketch a V vs t plot of the object
from the throw to the peak (use a = -10 m/s2)

A meter stick of negligible mass is fixed horizonally at its 100 cm mark.imagine this meter stick used as a displayfor some fruits and vegetables with record-breaking masses.a lemon with mass of 3.9kg hangs from the 70cm mark and a cucumber with a mass of 9.1kg hangs from the xcm mark .what is the value of x if the net torque acting on the meter stick is 56N in the counter clockwise direction.