Mechanics | Relativity Answers

A particle P is let fall vertically from a height to the ground. Another particle Q is projected vertically down 3s later with a velocity of 3m/s^s from the same height. If both particles reached the ground simultaneously. Calculate:

a. time by each particle to reach the ground

b. distance travelled by each particle to reach the ground.

A stationary ball is struck by a bat with an avg force of 60N over 10 ms. If the mass of the ball is .25 kg, what speed does it have just after the impact?

The kinetic energy of an object is increased by a factor of 8, by what factor is the magnitude of its momentum changed?

Find the minimum initial speed of a cork that pops out of a bottle and which travels a horizontal distance of 10 m.

A direct compressive force of 240,000 N is applied to a solid piece of material of rectangular cross-section, 8 cm by 5 cm.

A cyclist knows the total mass of her self and her bicycle. She also knows how far she can coast when slowing down from a given speed. How could she use this information to determine the average resistance opposing her motion?

Joe Mauer hits the homerun of his life putting a baseball into the orbit of the Earth. The mass of the Earth is 5.98 x 1024 kg, the mass of the baseball is 0.15 kg and the distance between the center of mass of the Earth and the center of mass of the baseball is 6.8 x 106 m. Calculate the gravitational force (in N) between the baseball and the Earth.



Joe Mauer hits the homerun of his life putting a baseball into the orbit of the Earth. The mass of the Earth is 5.98 x 1024 kg, the mass of the baseball is 0.15 kg and the distance between the center of mass of the Earth and the center of mass of the baseball is 6.8 x 106 m. How fast (in m/s) is the baseball moving around the Earth?


Suppose a hypothetical planet with the same mass as the Earth’s has a radius that is 1/3 of Earth’s radius. What is the acceleration due to gravity (in m/s2) on that hypothetical planet?

Spiderman uses his spider webs to save a runaway train moving about 80 km/h , (Figure 1). His web stretches a few city blocks (600 m ) before the 104-kg train comes to a stop

What is the spring constant of a spring of negligible mass which gained 7.3 joules of potential energy as a result of being compressed 0.42 meters?

A cricket shoe has 10 cleats (nails) in sole, each have area of 1.65 x 10 -2cm 2in contact with the floor. During walking there is one instant when all 10 cleats support the entire weight of 80 kg person. What is pressure exerted by the nails on the floor?