Work
A crate of mass 50kg is pushed along a floor with a force of 20N fo a distance of 5m. Calculate the work done.
100 N
A block with a mass of 5.7 kg slides on a frictionless table with a speed of 1.2 m/s. It is brought to rest by compressing a spring in its path. By how much is the spring compressed if its force constant is 1500 N/m?
7.4cm
If 150 Joules of work is needed to move a box 10 meters, what force was used?
15 N
What is the Kinetic Energy of a 150kg object that is moving with a speed of 15m/s?
KE = 16875J
Is nuclear energy a form of potential energy?
Yes
Calculate the work done by a force of 30 N in lifting a load of 2kg to a height of 10m (g = 10ms-2)
300 J
Assume the force of gravity to be constant for small dis- tances above the surface of the earth. A body is dropped from rest at a height h above the earth’s surface. If we ignore air resistance, what will its kinetic energy be just before it strikes the ground?
r2gh
What is the average power generated by Peter Quill aka Star Lord (m = 100 kg) running up a flight of stairs rising vertically 6 .0 m in 5.0 s?
1176 W
An object has a kinetic energy of 25J and a mass of 34kg, how fast is the object moving?
v = 1.28 m/s
A fruit hangs from a tree and is about to fall to the ground of 10 meters height. It has a potential energy of 22.5 J. Calculate the mass of the fruit
0.229 kg
A ball with a velocity of 5 m s-1 impinges at angle of 60˚ with the vertical on a smooth horizontal plane. If the coefficient of restitution is 0.5, find the velocity and direction after the impact.
The impulse on the ball acts perpendicular to the smooth plane.
The diagram below represents how water is funnelled into a pipe and directed to aturbine at a hydro- electric power plant. The force of the falling water rotates theturbine. Each second, 200 m3 of water is funnelled down a vertical shaft to the turbine below. The vertical height through which the water falls upon reaching the turbine is 150 m.
1,96x106 N
At the start of a ski jump, a skier begins at rest at the top of a hill. What types of energies are present?
Gravitational
An object moving with a speed of 35m/s and has a kinetic energy of 1500J, what is the mass of the object?
m = 2.45kg
An object of mass 30 kgs is placed on a hill top of height 80m. What is the potential energy possessed by the object?
23520 J
A bullet of mass 20 g strikes a pendulum of mass 5 kg. The center of mass of pendulum rises a vertical distance of 10 cm. If the bullet gets embedded into the pendulum, calculate its initial speed.
v = 351.4m s-1
The net work done by a net force acting on an object is equal to the change in the kinetic energy of the object.
Work-Kinetic Energy Theorem
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 v1 of a swimmer reaching the bottom of slide 1 compare with v2, the speed of a swimmer reaching the end of slide 2?
v1 = v2
What is the Kinetic Energy of a 1200kg object that is moving with a speed of 24m/s?
KE = 345,600 J
5 kg weighing cat climbing at the top of the tree has a potential energy of 1176 kg. Find the height of the tree?
24 cm
A body of mass 5kg is thrown up vertically with a kinetic energy of 1000 J. If acceleration due to gravity is 10ms-2, find the height at which the kinetic energy becomes half of the original value.
g = 10m s-2
When my velocity triples, my kinetic energy increases by ______ times.
9
What is the power required to lift a 10 kg object 5 m in the air in 2 s?
250 W
An object has a kinetic energy of 14J and a mass of 17kg, how fast is the object moving?
v = 1.28m/s
A skier is at the top of a hill. At the bottom of the hill, she has a velocity of 12ms. How tall was the hill?
7.35m