A tennis ball is lightly thrown vertically upwards to be struck by the racquet at the peak of the trajectory of the ball. A 350 g tennis racquet hits the ball with a velocity of 30. m⋅s−1. Both racquet and ball move with a horizontal velocity of 25 m⋅s−1 immediately after the collision. What is the mass of the ball, in grams?

Calculate the ratio of h+ ions to oh– ions at a ph = 6. find the concentration of h+ ions to oh– ions listed in table b of your student guide. then divide the h+ concentration by the oh– concentration. record this calculated ratio in table a of your student guide. compare your approximated and calculated ratios of h+ ions to oh– ions at a ph = 6. are they the same? why or why not? record your explanation in table a. what is the concentration of h+ ions at a ph = 6? mol/l what is the concentration of oh– ions at a ph = 6? mol/l what is the ratio of h+ ions to oh– ions at a ph = 6? : 1

If the work required to stretch a spring 3 ft beyond its natural length is 15 ft-lb, how much work is needed to stretch it 27 in. beyond its natural length?

Photons with the highest energy have the longest period