Q 7

Swimmers at a water park have a choice of two frictionless water slides as shown in the figure.Although both slides drop over the same height,h,slide 1 is straight while slide 2 is curved,dropping quickly at first and then leveling out.How does the speed v_{1} of a swimmer reaching the end of slide 1 compares with v_{2},the speed of a swimmer reaching the end of slide 2?
A) v_{1} > v_{2}
B) v_{1} < v_{2}
C) v_{1} = v_{2}
D) No simple relationship exists between v_{1} and v_{2} because we do not know the curvature of slide 2.

Q 8

Two stones,one of mass m and the other of mass 2m,are thrown directly upward with the same velocity at the same time from ground level and feel no air resistance.Which statement about these stones is true?
A) The heavier stone will go twice as high as the lighter one because it initially had twice as much kinetic energy.
B) Both stones will reach the same height because they initially had the same amount of kinetic energy.
C) At their highest point, both stones will have the same gravitational potential energy because they reach the same height.
D) At its highest point, the heavier stone will have twice as much gravitational potential energy as the lighter one because it is twice as heavy.
E) The lighter stone will reach its maximum height sooner than the heavier one.

Q 9

Two identical balls are thrown directly upward,ball A at speed v and ball B at speed 2v,and they feel no air resistance.Which statement about these balls is correct?
A) Ball B will go twice as high as ball A because it had twice the initial speed.
B) Ball B will go four times as high as ball A because it had four times the initial kinetic energy.
C) The balls will reach the same height because they have the same mass and the same acceleration.
D) At its highest point, ball B will have twice as much gravitational potential energy as ball A because it started out moving twice as fast.
E) At their highest point, the acceleration of each ball is instantaneously equal to zero because they stop for an instant.