Mechanics | Relativity Answers

A ball is thrown from the edge of the top of a building with an initial velocity of 80.3 km/hr at an angle of 52.5 degree above the horizontal. The ball hits the ground a horizontal distance of 108 from the base of the building. Assume that the ground is level and that the side of the building is vertical. Calculate the height of the building.

The position of a particle is given by r(t) = -3.1 t i + 0.72 t4 j m, where t is in seconds. At t = 1.9 s, what is the magnitude of the particle’s acceleration?

A man of weight 500N standing on a platform P supported by two light strings passing over two light smooth pulleys A and B supports himself by pulling the string. If the weight of the platform is 1000N, what is the force exerted by the man on the string to keep the platform?

A tennis ball of mass 0.0551kg is served. It strikes the ground with a velocity of 54.0m/s at an angel of 22° below the horizontal. Just after the bounce it is moving at 53.0m/s at an angel of 18° above the horizontal. If the interaction with the ground lasts 0.0610 s, what is the magnitude of the average force exerted by the ground on the ball?

An archer shoots an arrow towards a 300g target that is sliding in her direction at a speed of 2.50m/s on a smooth frictionless surface. The 22.5g arrow is shot with speed of 35m/s and passes through the target without changing the mass of the target, which is stopped by the impact. Calculate the speed of the arrow after passing through the target?

Two particles have a total mass of 10.0g. Particle A is located on the x-axis at xA=2.0 cm, while particle B is located on the x-axis at xB=4.0 cm. The center of mass of this two-particle systems is located at xcm=3.4 cm. Calculate the mass of each particle?

Two trains on separate tracks move toward each other. Train 1 has a speed of 130 km/h; train 2, a speed of 90.0 km/h. Train 2 blows its horn, emitting a frequency of 500 Hz. What is the frequency heard by the engineer on train 1 when the air temperature is 16^oC?

A cargo truck blow its horn and can be heard at a distance of 10.0 m with a sound intensity level 93.0 dB. If 6 identical cargo trucks simultaneously blow their horns, what combined sound intensity level can be heard at a distance of 10.0 m form these trucks?

A person wears a hearing aid that uniformly increases the intensity level of all audible frequencies of sound by 30.0 dB. If the hearing aid picks up a sound with an intensity of 3.5 x 10^-9 W/m² , what is the sound intensity delivered to the eardrum?

A body of mass 10 kg and initially at rest is subjected to a force of 20N for a distance of 10m. Calculate the change in kinetic energy of the body