Mechanics | Relativity Answers

A bullet of mass 20 g, travelling at a speed of 350 m/s, strikes a steel plate at an angle of 30 degree with the plane of plate. it ricochets off at the same angle, at a speed of 320 m/s. What is the magnitude of the impulse that the steel plate gives to the projectile ?If the collision with the plate takes place over a time delta t=10^3 s, what is the average force exerted by the plate on the bullet?

The motion of a particle is defined by the relation S=2t3-15t2+24t+4 where S is expressed in metres and t in seconds. Determine when the velocity is zero

A solid body rotates about a stationary axis so that its angular velocity depends on the rotational angle $ as a = COQ - faj) where C0Q and k are positive constants. At the moment f = 0, (j> = 0, the time dependence of rotation angle is:

Particles are released from rest at A and slide down the smooth surface of height h to a conveyor B. The correct angular velocity (0 of the conveyor pulley of radius r to prevent any sliding on the belt as the particles transfer to the conveyor is

Two particles A and B having mass m each and charge q1 and -q2 respectively, are connected at the ends of a non conducting flexible and inextensible string of the length I. The particle A is fixed and B is whirled along a vertical circle with centre at A. If a vertically upward electric field of strength E exists in the space, then for minimum velocity of particle B :
(a) the tension force in string at lowest point is zero
(b) the tension force at the lowest point is non-zero
(c) the tension force at the highest point is zero
(d) the work done by interaction force between particles A and B is non-zero

A wheel of radius R is rolling in a straight line without slipping on a plane surface, the plane of the wheel is vertical. For the instant when the axis of the wheel is moving with a speed v relative to the surface, the instantaneous velocity of any point P on the rim of the wheel relative to the surface will be

The position vector of two particles of mass 4.0 kg and 2.0 kg are, respectively,
r 3 �i �j 2 k� 2
1 = t + t + t
r
and r 3�i ( 1)�j 4 k� 2
2 = + t - + t
r
where t is in seconds and the position
in metres. Determine the position vector of the centre of mass of the system, the
velocity of the cm and the net force acting on the system.

In an arcode video game a spot is programmed to move across the screen to x=9.00t-0.750t^3, where x is the distance in cm and t is the time in seconds. when the spot reaches a screen edge, at either x=0 or x=15.0cm. t is reset to 0 and spot start moving again according to x(t)
a) at what time after starting is the spot instantaneously at rest.
b) where does it occur
c) what is its acceleration when it occurs
d)in what direction is it moving just prior to coming to rest.
dii)just after
e) when does it first reach an edge of the seven after t=0.

Define mean free path of a molecule in a gas. Derive the law of distribution of free paths

A ball drops from 180 metres and rebounds one-third of its previous height on each bounce.
i) Find the total distance it travels before it comes to rest.
ii) Find the total distance traveled uptill the time the ball strikes the ground fifth time.