A student is pushing a desk across the floor of the classroom. Even though there is friction, the desk still accelerates to the right. Answer the following questions concerning the desk. The student took 90 seconds to move the desk 15 feet across the room? What was the desk's velocity? What was the desks rate of acceleration? What is the net force used by the student to move the desk?

Aball bearing at 220.0 °c is dropped into a cup containing 250.0 g of water at 20.0 °c. the water and ball bearing come to a temperature of 30.0 °c. what is the heat capacity of the ball bearing in j/°c? (hint: how are the algebraic signs of q related for the ball bearing and the water? )

What would the difference of spectral lines emitted by hydrogen gas in distant galaxies which is normally found at a wavelength of 21 cm on earth, be observed at 21.1 centimeters?

Will give brainliest! jay rides his 2.0-kg skateboard. he is moving at speed 5.8 m/s when he pushes off the board and continues to move forward in the air at 5.4 m/s. the board now goes forward at 13 m/s. a. determine jay’s mass. b. determine the change in the internal energy of the system during this process.(express your answer to two significant figures and include the appropriate units.)