Power and Energy

Work, Power and Energy

by Lety Alvarez

According to the following data, how much work does the completely horizontal applied force do?

Fapp = 40 N,     Fk = 10 N,    m= 3 kg,   x= 8 m

  

320 J​

Multiple Choice

According to the data provided, how much work does the weight do?

F = 40 N, Fk = 10 N, m= 3 kg, x= 8 m

• 40 J

• 0 J

• 320 J

• 400 J

An object is displaced along a horizontal surface by a force of 15 N by a distance of 10 m. The kinetic friction force is 7.5 N.  What is the work of the resultant force?

​

75 J​

What is the kinetic energy of a 12 kg car when it moves at a speed of 29 km/h?

​

389 J

Multiple Choice

An object of 2.03 kg is thrown vertically upwards at an initial speed of 10.41 m/s. What is the kinetic energy at the moment it is thrown?

• 110 J

• 1200 J

• 2.03 J

• 10.41 J

A projectile is launched with a velocity of 676 km/h, right at the moment of launch it has a kinetic energy of 1105 J.  What is the mass in grams of the projectile?

​

62 g​

Multiple Choice

An object of mass 0.328 kg moves along a straight path at a constant velocity.  If the kinetic energy is 14.7 J, determine the speed of the object.

• 12.34 m/s

• 0 m/s

• 9.47 m/s

• 5.16 m/s

A 4.85 kg box is placed on an 80 cm table. What is the potential energy of the box when it is on the table?

​

38​ J

Multiple Choice

A 0.050 kg stone is dropped from a height of 15.67 m.  What is the potential energy at the instant of release?

• 3.44 J

• 0 J

• 5.98 J

• 7.68 J

Multiple Choice

A 4.3 kg box on a platform has a potential energy of 349 J.  Determine the height of the platform.

• 0 m

• 8.27 m

• 9.81 m

• 2.43 m

Multiple Choice

An object held at a height of 3.7 m has a potential energy of 209 J.  What is the mass of the object?

• 5.76 kg

• 8.97 kg

• 4.32 kg

• 11.98 kg

​

A projectile of 0.12 kg is thrown vertically downwards with a velocity of 9.35m/s and from a height of 13m.  What is the mechanical energy at the moment it is thrown?

​

20 J

Multiple Choice

A box of mass 4.04 kg is thrown vertically downwards with a speed of 7.92 m/s from a height of 11.44 m.  How much mechanical energy does the box have?

• 126.7 J

• 453.4 J

• 0 J

• 580.1 J

Multiple Choice

When an object is dropped from a certain height it has a potential energy of 396J.  How much mechanical energy does the object have falling to half its original height?

• 396 J

• 0 J

A 250 g bag is thrown vertically upwards with a speed of 4 m/s. What is the potential energy at the time the bag reaches its maximum height?

​

2 J

​A 150g projectile is launched vertically upward with a speed 34.39 m/s.  What is the maximum height of the projectile?

​

60 m

Multiple Choice

A bag of 204 g is thrown vertically upwards with a speed of 8 m/s.  What is the potential energy of the bag reaching maximum height?

• 6.53 J

• 8.96 J

• 11.99 J

• 23.87 J

A container is thrown vertically downwards, at the moment it is thrown it has a kinetic energy of 22.32 J and a potential energy of 46.08 J. What is the kinetic energy the instant before it hits the ground?

​

68.4 J

Multiple Choice

​A ball of mass 220g falls freely from a table of height 57.8 cm. At what speed does the ball hit the ground?

• 1.25 m/s

• 12.43 m/s

• 3.37 m/s

• 9.88 m/s