A200 g projectile is fired with a velocity of 900 m/s toward the center of a 15 kg wooden block which rests on a rough surface.

if the projectile penetrates and emerges from the back at a velocity of 300 m/s, determine the velocity of the block just after the projectile emerges.

how long does the block slide on the rough surface after the projectile emerges before it comes to rest again?

the coefficient of kinetic friction between the block and surface is 0.2.

Abrake has a normal braking torque of 2.8 kip in and heat-dissipating cast-iron surfaces whose mass is 40 lbm. suppose a load is brought to rest in 8.0 s from an initial angular speed of 1600 rev/min using the normal braking torque; estimate the temperature rise of the heat dissipating surfaces.

An electric motor is used to drive a power press which makes steel turning moment diagrams 323 pressings from a metal sheet. the motor runs at a mean speed of 50 rev/s. the torque required is 10.0nm for 0.2s, followed by 1.0nm for0.3 s with this sequence then being repeated. what is the minimum power required of the motor and the moment of incrtia required for the t1ywhcel if the speed fluctuations are to be restricted to 1.5%?

Tom is having a problem with his washing machine. he notices that the machine vibrates violently at a frequency of 1500 rpm due to an unknown rotating unbalance. the machine is mounted on 4 springs each having a stiffness of 10 kn/m. tom wishes to add an undamped vibration absorber attached by a spring under the machine the machine working frequency ranges between 800 rpm to 2000 rpm and its total mass while loaded is assumed to be 80 kg. a) what should be the mass of the absorber added to the machine so that the natural frequency falls outside the working range? b) after a first trial of an absorber using a mass of 35 kg, the amplitude of the oscillation was found to be 10 cm. what is the value of the rotating unbalance? c) using me-3.5 kg.m, find the optimal absorber (by minimizing its mass). what would be the amplitude of the oscillation of the absorber?