How Is Work and Kinetic Energy Calculated in Physics Problems?

In summary, the conversation discusses various problems related to work, potential energy, kinetic energy, and velocity. The first question asks about the work done by gravity on a book falling from a shelf, with possible answers being 1.2 J, 7.5 J, 24.5 J, or 73.5 J. The second question asks for the minimum amount of work done by a hydraulic lift to raise a 150-kg aluminum block 2.0m vertically, with options of 75 J, 300 J, 1470 J, or 2940 J. The third question relates to the kinetic energy of a 100-kg car at the bottom of a 50 m hill, with possible answers
  • #1
Junebugg
1
0

Homework Statement



6. A 2.5-kg book slides horizontally and falls from a shelf 3.0m above the floor. How much work does the force of gravity do on the book as it falls 3.0m?
F. 1.2 J
G. 7.5 J
H. 24.5 J
J. 73.5 J

7. Which of the following is the minimum amount of work done by a hydraulic lift to raise a 150-kg aluminum block 2.0m vertically?
A. 75 J
B. 300 J
C. 1470 J
D. 2940 J

8. The motion of roller coasters depends upon the conversion of potential and kinetic energy. a 100-kg car starts from rest at the top of a hill with a height of 50 m. Which of the following is this car's kinetic energy at the bottom of the hill?
F. 150 J
G. 5000 J
H. 49,000 J
J. 98,000 J

9. A 0.25-g paint chip comes off a satellite orbiting Earth. The velocity of the paint chip is 7000 m/s. Which is the kinetic energy of the paint chip?
A. 1750 J
B. 6125 J
C. 12,250 J
D. 24,500 J

10. An automobile was moving at 15 m/s and accelerated at 2 m/s^2 for 2 s. Which was its final speed?
F. 17 M/S
G. 25 M/S
H. 27 M/S
J. 35 M/S

Homework Equations


ke=1/2mv^2



The Attempt at a Solution


for 8 I'm getting G or H
for 9 I'm getting A or B
for 10 I'm getting J
 
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  • #2
Pls post your working.
 

Related to How Is Work and Kinetic Energy Calculated in Physics Problems?

1. What is kinetic energy?

Kinetic energy is the energy an object possesses due to its motion. It is directly proportional to the mass and velocity of the object.

2. How do you calculate kinetic energy?

The formula for calculating kinetic energy is KE = 1/2 * m * v^2, where KE is kinetic energy, m is the mass of the object, and v is the velocity of the object.

3. What is the unit of measurement for kinetic energy?

The unit of measurement for kinetic energy is Joules (J).

4. Can kinetic energy be negative?

No, kinetic energy cannot be negative. It is always a positive value, as it represents the energy an object possesses due to its motion.

5. How does kinetic energy relate to potential energy?

Kinetic energy and potential energy are two forms of mechanical energy. Kinetic energy is the energy an object possesses due to its motion, while potential energy is the energy an object possesses due to its position or state. In many cases, potential energy can be converted into kinetic energy and vice versa.

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