Two rocks are tied to massless strings and whirled in nearly horizontal circles so that the time to travel around the circle once is the same for both. one string is twice as long as the other. the tension in the longer string is twice the tension in the shorter one. what is the mass m of the rock at the end of the shorter string compared to the mass m2 of the rock at the end of the longer one? a. m1 = m2/4 b. m1=m2 c. m m2 d. m1=2m2 e. m1= 4m2

Suppose a soccer ball is kicked from the ground at an angle 20.0º above the horizontal at 8.00 m/s. the y-velocity is determined to be 2.74 m/s. how long will the ball be in the air? assume the ball lands at the same height at which it was kicked.

In a classical model of the hydrogen atom, the electron moves around the proton in a circular orbit of radius 0.053 nm. what is the electron's orbital frequency? what is the effective current of the electron?

Suppose a force of 60 n is required to stretch and hold a spring 0.1 m from its equilibrium position. a. assuming the spring obeys hooke's law, find the spring constant k. b. how much work is required to compress the spring 0.5 m from its equilibrium position? c. how much work is required to stretch the spring 0.6 m from its equilibrium position? d. how much additional work is required to stretch the spring 0.1 m if it has already been stretched 0.1 m from its equilibrium? a. kequals 600