Why is our day on earth 24 hours long

A ballet student with her arms and a leg extended spins with an initial rotational speed of 0.90rev/s. As she draws her arms and leg in toward her body, her rotational inertia becomes 0.80 kg⋅m2 and her rotational velocity is 4.1rev/s.

A 15.0-kg block is dragged over a rough, horizontal surface by a 75-n force acting at 21° above the horizontal. the block is displaced 5.7 m, and the coefficient of kinetic friction is 0.200. (a) find the work done on the block by the 75-n force.

Eddie set up a science experiment with plants. He bought three small tomato plants, all about the same size and height, and set them all in his front window.

Once a 26 kg crate is in motion on a horizontal floor, a horizontal force of 57 N keeps the crate moving with a constant velocity. The acceleration of gravity is 9.81 m/s 2.

If net force of 25 n is exerted over distance of m to the right on 2 kg mass initially at rest and moved it what is final velocity

ngrid kicks a football with an initial velocity of 12 m/s at an angle of 45° relative to the ground. The horizontal component of the initial velocity to the nearest tenth is m/s.

A 60-watt light bulb has a voltage of 120 volts applied across it and a current of 0.5 amperes flows through the bulb. What is the resistance of the light bulb?

In a laboratory experiment, a diffraction grating produces an interference pattern on a screen. If the number of slits in (including the slit spacing) the same, then The fringes stay the same brightness and get closer together.

The gravitational potential has a zero value gravitational field in the same place is? Maximum or null indeterminate

In four-seater countries, temperature drops below 0 ° C during peak winter. Why only the frozen surface of the water instead of the whole river and the lake freezes?