Download Physics test two with Gerald Votta and more Exams Physics in PDF only on Docsity!
Physics I – Test # 2. NAME_____________________________
1. The weight of an astronaut plus his space suit on the Moon is only 255 N. Part (a) How
much do they weigh on Earth, in newtons, assuming the acceleration due to gravity on
the moon is 1.67 m/s^2?
Part (b) What is the mass of the astronaut and his space suit on the Moon, in kilograms?
2. Two blocks are connected by a massless rope. The rope passes over an ideal (frictionless
and massless) pulley such that one block with mass m 1 = 11.5 kg is on a horizontal table
and the other block with mass m 2 = 17.5 kg hangs vertically. Both blocks experience
gravity and the tension force, T. Draw a figure and calculate the acceleration of the
system.
3. A contestant in a winter sporting event pulls an m kg block of ice across a frozen lake by applying a force F at an
angle θ above the horizontal as shown. Assume that the coefficient of static friction for ice on ice is 0.0300, and the coefficient of kinetic friction for the same is 0.0100. Let to the right be the positive x direction and up be the positive y direction for your equations. Part (a) Enter an expression for the net force in the horizontal direction, Σ F x. Part (b) Enter an expression for the net force in the vertical direction, Σ F y.
4. The propeller of a World War II fighter plane is 2.05 m in diameter.
Part (a) What is its angular velocity in radians per second if it spins at 1100 rev/min?
Part (b) What is the linear speed (in m/s) of its tip at this angular velocity if the plane is stationary on the tarmac? Part (c) What is the centripetal acceleration of the propeller tip under these conditions? Represent your answer in meters per second squared.
7. A 75 - kg man pushes a crate 2.5 m up along a ramp that makes an angle of 15 ° with the horizontal. He exerts a
force of 475 N on the crate parallel to the ramp and moves it at a constant speed. Part (a) Calculate the work, in joules, that the man performs to cause the crate and himself to move up the ramp.
8. A runaway train car that has a mass of 12500 kg travels at a speed of 5.1 m/s
down a track. Part (a) Compute the time required, in seconds, for a force of
1250 N to bring the car to rest.
9. A ball with an initial velocity of 5.5 m/s and
mass 1.1 kg moves at an angle 50.5 ° above the
horizontal. The ball hits a vertical wall and
bounces off so that it is again moving at 50.5 °
above the horizontal with the same speed. See
the figure.
Part (a) What is the magnitude of the impulse delivered by the wall, in kilogram meters per second?
10. During a circus act, a performer thrills the crowd by catching a cannon ball shot
at him. The cannon ball has a mass of 7.5 kg and the horizontal component of its
velocity is 7.5 m/s when the 61.5 - kg performer catches it. Part (a) If the
performer is on nearly frictionless roller skates, what is his recoil speed, in
meters per second?
I, ________________________ , pledge that all the work performed on this exam is my own work, with consultation of only my textbook, notes, mathematical handbook or clarifications from the course instructor. Signed: ___________________________ Date: ___________
