Ablock of mass m is dropped from the fourth floor of an office building and hits the sidewalk below at speed v. from what floor should the block be dropped to double that impact speed?

Using a pedometer, you walk 3000 steps in 20 minutes, so your speed is 150 steps/min. each of your steps is 0.7 m long. what is your speed? 150 steps/min=/s=/h

Suppose that 27 j of work is needed to stretch a spring from its natural length of 6 m to a length of 9 m. (a) how much work is needed to stretch the spring from 12 m to 14 m? j (b) how far beyond its natural length will a force of 78 n keep the spring stretched?

For waves in the ocean, the medium of the waves is a. air b. water c. energy d. a passing boat