Frank Says That If You Release the String When Swinging
Frank says that if you release the string when swinging a ball in a horizontal circle,the ball flies out in the radial direction defined by the string at the instant you release the ball.John says that it flies out along a tangent line perpendicular to the string,and that it then drops straight down to the ground.Which one,if either,is correct?
A)Frank,because the centrifugal force is no longer counteracted by the string.
B)Frank,because balls naturally fly straight out.
C)John,because there is no centrifugal force.
D)John,because balls fall straight down when released.
E)Neither,because although there is no centrifugal force,and the ball's velocity is tangent to the circle at the instant of release,the ball then follows a parabolic trajectory.
The coefficient of static friction for the tires of a race car is 0.950 and the coefficient of kinetic friction is 0.800.The car is on a level circular track of 50.0 m radius on a planet where compared to Earth's .The maximum safe speed on the track on the planet is ____ times as large as the maximum safe speed on Earth.
The coefficient of static friction for the tires of a race car is 0.950 and the coefficient of kinetic friction is 0.800.The car is on a level circular track of 50.0 m radius on a planet where compared to Earth's .If the car is to be able to travel at the same speed on the planet as on Earth,the radius of the track on the planet must be ____ times as large as the radius of the track on Earth.
The following equation was obtained by solving a physics problem: The best physical representation of the situation is
A)A car traveling at 16.0 m/s is 19.2 into a turn of a quarter circle on a level road.
B)A mass on a string that is originally horizontal has fallen to where the angle between the string and the vertical direction is 19.2.
C)A mass on a string originally horizontal has fallen 19.2 from the horizontal direction.
D)A car traveling at 16.0 m/s is on a circular curve banked at 19.2.
E)A car traveling at 16.0 m/s and going over a semicircular mountain-top road is 19.2 down from the top.