Mechanics | Relativity Answers

A 10-g bullet of unknown speed is shot horizontally into a 2-kg block of wood suspended from the ceiling by a cord. The bullet hits the block and becomes lodged in it. After the collision, the block and the bullet swing to a height 30cm above the original position. What was the speed of the bullet? (This device is called the ballistic pendulum). Take
g=9.8ms−2

Sand drops at the rate of 2000 kg/min. from the bottom of a hopper onto a belt conveyor moving horizontally at 250 m/min. Determine the force needed to drive the conveyor, neglecting friction.

How fast must a ball be rolled along the surface of a 70-cm high table so that when it rolls off the edge it will strike the floor at the same distance (70cm) from the point directly below the edge of the table?

A cart is moving horizontally along a straight line with constant speed of 30 m/s. A projectile is fired from the moving cart in such a way that it will return to the cart after the cart has moved 80 m. At what speed (relative to the cart) and at what angle (to the horizontal) must the projectile be fired?

A body hangs from a spring balance supported from the roof of an elevator. If the elevator has an upward acceleration of
3ms−2
and the balance reads 50 N, what is the true weight of the body?

A 150-kg ladder leans against a smooth wall, making an angle of 30 degrees with the floor. The centre of gravity of the ladder is one-third the way up from the bottom. How large a horizontal force must the floor provide if the ladder is not to slip?

A wave is represented by y=asin(At-Bx+C);(A,B,C=Constants).The dimensions of aBC/A are as those of-
A)Velocity B)Length C)Mass D)Time

:
Two basketball players run into each other. Player 1, with a mass of 55.0 kg, experiences a –15.6 m/s2 acceleration. If player 2 has a mass of 48.5 kg, she experience and acceleration of ____ m/s2 immediately following the collision.

A simple harmonic oscillator has amplitude a angular velocity ω and mass m. then average energy in one time period will be

The minimum energy required to launch a m kg satellite from earth surface in a circular orbit at a height 2 r will be