Classical Mechanics Answers

When a person standing on a ground is an observer and a passenger in a train moving in front of him is in motion with respect to him
But I want to ask that when the passenger is considered to be observer then the man standing outside train is in motion or rest with respect to passenger

A wheel having a moment of inertia of 1.0 kg m2
, is rotating about an axis through its centre and perpendicular to its plane, at a speed of 30 rad s−1. Due to friction on its axis, it comes to rest in 10 minutes. Calculate i) the total work done by friction, ii) average torque exerted by the force of friction and iii) the angular momentum of the wheel 2 minutes before it stops rotating.

A cylindrical drum has a radius of 0.45 m and is initially at rest. It is then given an angular acceleration of 0.40 rad s−2. At time t = 8.0 s calculate (i) the angular speed of the drum, (ii) the centripetal acceleration of a point on the rim of the drum, (iii) the tangential acceleration at that point, and (iv) the resultant acceleration at that point.

A steel ball A of mass 20.0 kg moving with a speed of 2.0 ms−1
collides with another ball B of mass 10.0 kg which is initially at rest. After the collision A moves off with a speed of 1.0 ms−1 at an angle of 30º with its original direction of motion. Determine the final velocity of B.

A satellite moves in an elliptical orbit with the Earth at one focus. At the perigee its
speed is v and its distance from the centre of the Earth is R . If the eccentricity of its
orbit is 0.5, calculate its speed at the apogee.

A projectile is projected with a speed 30 m/s at an angle 30° with the vertical. The speed of the projectile when its direction of motion makes an angle 30° with the horizontal is ? Options 1 ) 10 m/s
2) 20 m/s , 3) 10*3^2 4) 20*3^2

A ball is kicked such that it leaves the ground at an upwards angle of 35° above the horizontal with an initial velocity of 17 m s−1.

How far away does the ball hit the ground? (in m to 2.s.f)

(note: ignore the effects of air resistance when solving this problem)

After stealing a 20 kg bag of oranges, a 80 kg thief finds himself at rest on a frozen lake. He attaches himself to the bag of oranges with a long rope and pushes himself off from the bag by giving himself a rightward velocity. When the rope runs out:

A) both will move right because the thief has a larger kinetic energy
B) both will move right because the thief has a larger mass
C) both will move left because the thief has a larger kinetic energy
D) both will move left because the thief has a larger mass
E) both will stop

At t= 0, a block of mass m is projected with speed v on a rough long horizontal plank (of mass 3m) placed on smooth ground, as shown. Work done by friction on the block between t= 0 and t= infinity equals

you drop a stone in a well and hear it hit the bottom in 6.19s how deep is the well