What is the mass of an object if it is moving at a speed of 10 m/s and has 400 J of kinetic energy?

When you drop a pebble from height a it reaches the ground with speed v if there is no air resistance. from what height should you drop it so it will reach the ground with three times the speed? (a) 9m (b) 3m (c) 6m (d) 18m

Jason is a body builder. despite being more fit, he weighs more than his brother ryan, who is the same height. which is a possible reason? a. jason has more muscle mass than ryan does. b. jason has more body fat than ryan does. c. jason has more muscle mass and body fat than ryan does d. jason has less body fat than ryan does.

An electric clothes dryer has a resistance of 8 ohms. it draws 30 a of current. what is the voltage, in volts, of the wall outlet that it is plugged into?