15 A rock falls freely from the top of a building of height 122.5 m. If the free fall acceleration equals 9.8 m/s, calculate the rock’s velocity before it reaches the ground by one second.

A2 kg ball travellng to the right with a speed of 4 m/s collidees with a 5 kg ball traveling to the left with a speed of 3 m/s. take right to be the positive direction. what is the total momentum of the two balls before they collide? what is the total momentum of the two balls after they collide?

If the radius of curvature of the cornea is 0.75 cm when the eye is focusing on an object 36.0 cm from the cornea vertex and the indexes of refraction are as described before, what is the distance from the cornea vertex to the retina? express your answer to two significant

The radius of a sphere is increasing at a rate of 9 cm/ sec. find the radius of the sphere when the volume and the radius of the sphere are increasing at the same numerical rate.