A snowboarder drops from rest into a halfpipe of radius R and slides down its frictionless surface to the bottom (a) Show that the snowboarder's speed at the bottom of the halfpipe is
v = 2gR (use conservation of energy)
(b) Show that the snowboarder's centripetal acceleration at the bottom is
ac = 2g (Apply the expression for centripetal acceleration)
(c) Show that the normal force on the snowboarder at the bottom of the halfpipe has a magnitude of 3mg (Use Newton's second law of motion)

The coefficient of friction is a number that represents the resistance to sliding between two in contact with one another.

Awater balloon launcher uses an elastic band with a spring constant of 115 n/m to use thee launcher you stretch thee band back with a balloon n it the water balloons have a mass of 1.3 kg a) if you stretch the band by 0.8 m, what elastic force will the band exert? b) with the band stretched 0.8 m, how much elastic potential energy is stored in the spring? c) if you release the band, it pushes forward. what is the kinetic energy of the balloon when it reaches the natural length of the band? d) what is the speed of the balloon when it reaches the natural length of the band?

Consider a u-tube whose arms are open to the atmosphere. now equal volumes of water and light oil (ρ = 49.3 lbm/ft3) are poured from different arms. a person blows from the oil side of the u-tube until the contact surface of the two fluids moves to the bottom of the u-tube, and therefore, the liquid levels in the two arms are the same. if the fluid height in each arm is 30 in, determine the gage pressure exerted by the person on the oil by blowing.