Physics Work,Power & Energy Level: High School
A 2.00 kg ball is attached to a ceiling by a 1.00 m long string . The height of the room is 3 m . what is the gravitational potential of the ball relative to :a) the ceiling ?
b) the floor ?
c) a point at the same elevation as the ball ?
Physics Work,Power & Energy Level: High School
An object of mass 15.0 kg is pushed by a constant horizontal force of 100 newtons across a horizontal floor , with a coefficient of kinetic friction = 0. 150 , until it has a speed of 8.0 m/s . How far has it traveled , if we assume that it started from east ?
Physics Work,Power & Energy Level: High School
A 60.0 kg man walks up a flight of stairs , a rise of 4 meters in 4.2 seconds . What average power did he apply ?
Physics Work,Power & Energy Level: High School
Approximately what running speed would an 80 kg pole-vaulter have to acquire to clear a bar 5.0 m off the ground ? Assume that the pole-vaulter's center of gravity is initially 1.0 m off the ground and that the vaulter clears the bar if his center of gravity just reaches the height of the bar.
Physics Work,Power & Energy Level: High School
a) A spring is hung from a ceiling and a 500 g mass is hung from it. This increases the length of the spring by 20.0 cm . what is the force constant k for the spring
b) If the same spring is moved from the ceiling to a wall and stretched horizontally so that the 500 g mass is displaced 40.0 from its equilibrium position , what is the stored potential energy in the spring ?
Physics Work,Power & Energy Level: High School
A workman pushes a 200 kg crate up a frictionless metal ramp of length 4. 00 m into the back of the truck (see figure below)a) If the angle made by the ramp with the ground is 25.0 degrees and the workman pushes the block at very slow , constant speed, how much work does he do ?
b) What is the increased gravitational potential energy of the crate
Physics Work,Power & Energy Level: High School
A 100 kg man pulls his 30 kg daughter on a sled with a rope that makes an angle of 40 degrees with respect to the ground.a) If the man exerts a force of 50.0 N and the slides moves 100 m , how much work does he do ?
b) If the man pulls horizontally on the sled, What force would he has to exert to do the same amount of work ?
Physics Work,Power & Energy Level: High School
A 60 kg women pushes a 20 kg suitcase on wheels a distance of 10 m by exerting a force of 2.0 N in the direction of motion, starting from rest.a) How much work does she do ?
b) If there were no friction acting on the suitcase, what would its final velocity be at the end of the 10 m distance ?
Physics Work,Power & Energy Level: High School
Three masses are positioned at the following coordinates : 3.0 kg at (3,2) ; 4.0 kg at (0,1); and 5.0 kg at (5,-7) . What are the coordinates of the center of mass of this system ?
Physics Work,Power & Energy Level: High School
A 10000 kg railroad car traveling at a speed of 24.0 m/s strikes an identical car at rest. If the cars lock together as a result of the collision, calculate how much of the initial kinetic energy is lost due to an inelastic collision ?
Physics Work,Power & Energy Level: High School
A 10000 kg railroad car traveling at a speed of 24.0 m/s strikes an identical car at rest . If the cars lock together as a result of the collision , what is there common speed afterward ?
Physics Work,Power & Energy Level: High School
A small bomb , of mass 10 kg is moving toward the north with a velocity of 5.0 m/s . It explodes into three fragments: a 5.0 kg fragment moving west with a speed of 8.0 m/s ; a 4.0 kg fragment moving east with a speed of 10 m/s ; and a third fragment with a mass of 1.0 kg . what is the velocity of the third fragment ? (Neglect air friction) .
Physics Work,Power & Energy Level: High School
Lisa runs up 4 flights of stairs in 22 s. she weighs 510 N. If each flight rises 310 cm :a) what is her change in potential ?
b) what average power (watts) was required during the 22 s ?
c) what minimum horsepower motor would be required to do this ?
Physics Work,Power & Energy Level: High School
A plant engineer , Donna purchases an electrical motor with has an output of 1500 hp . if it requires 1.20 MW of electricity , what is the efficiency of the motor ?
Physics Work,Power & Energy Level: High School
A simple pendulum , with a 4.4 kg mass and length 75 cm , is released from rest at an angle of 50 degrees .To what height does the mass swing on the other side ?
what is the speed of the mass at the bottom of the swing ?
