Mechanics | Relativity Answers

A wooden block with mass M = 3 kg is lying on a horizontal table. It is hit by a bullet with mass m = 5 g which moves horizontally. The bullet remains in the block after colliding with it. The block moves on the table a distance d = 25 cm. The coefficient of kinetic friction μk = 0.2. Find the starting speed of the bullet.

A boy is initially seated on top of hemispherical ice mound of radius R. He begins to slide down the ice with negligible initial velocity. Approximate ice as being frictionless. At what height H(in terms of R) does the boy lose contact with ice ?

A 1.05 m long rod whose weight is negligible is supported at its end by wire A
and B of equal length. The cross-section area of A is 1.00 mm2; that of B is 4.00
mm2. Young’s modulus of wire A is 2.40 1011 a  P ; that for B is1.60 1011 a  P . At
what point along the rod should a weight W be suspended to produce (a) equal
stress in A and B? (c) Equal strain in A and B?
8)

a 20 kg block starts from rest at the top of a 60 degree incline slides down the incline. there is a 0.1 coefficient on the ramp. the block then continues to slide along the horizontal surface where there is a 0.3 coefficient of friction. the block then slows, due to friction, until it comes to rest at point b

The car has 1t measure. Over the long motion friction force acts as gravity 0.1.What will be the withdrawal of his forces if he moves : a)uniformly rectilinearly , b)rectilinear so hastily rushed evenly to 2 m / s ^ , c)ascends the slope 1m. In every street 25m is that haste. , d)descends in the same slope with the same haste

a stunt cyclist attempts to jump over 18 buses, each 3m wide. the approach ramp is inclined at 30 degrees to the horizontal. what is the minimum velocity with which he must leave the approach ramp in order to reach the landing ramp?

4 holes of radius R are cut from thin square plate of side 4R and mass m. The moment of inertia of remaining part about z axis is?

A body with mass 5 kg is acted upon by a force F=(-3i+4j) N. If its initial velocity at t =0 is v =(6i-12j)msec^-1, the time at which it will just have a velocity along the y axis is
(1) never
(2)10sec
(3)2 sec
(4)15 sec

A simple pendulum of mass m is suspended from a string of length l. What constant horizontal force must be applied on it so that string makes a maximum angle 60 from vertical

an explosion takes place at a distance of 3 200 metres away from sound detector that detects only the sound coming from the ground the sound detector detects the sound signals at 0.64 and 0.80 seconds after the explosion find the depth of of the soft ground