Work done by a gravitational field refers to the energy transferred when an object moves within a gravitational field, typically near the Earth's surface. When an object is lifted against the force of gravity, work is done on the object, which is calculated using the formula W=mgh, where W is the work done, m is the mass of the object, g is the acceleration due to gravity, and h is the height the object is raised. Conversely, when an object falls freely under the influence of gravity, the gravitational field does positive work on the object, converting potential energy into kinetic energy. This concept is fundamental in understanding energy conservation in gravitational systems, illustrating how gravitational forces can perform work and affect the motion of objects.
What is the formula for calculating work done by a gravitational field when lifting an object?
The formula is W=mgh, where W is the work done, m is the mass of the object, g is the acceleration due to gravity, and h is the height the object is raised.
What happens to the work done by the gravitational field when an object falls freely?
When an object falls freely, the gravitational field does positive work on the object, converting potential energy into kinetic energy.
Is work done by a gravitational field always positive?
No, work done by a gravitational field can be positive, negative, or zero, depending on the direction of the force and the displacement of the object. For example, work is negative when an object is lifted against gravity.
How does the height affect the work done by a gravitational field?
The work done by a gravitational field increases with height; the higher the object is lifted, the more work is required to overcome the gravitational force.
If an object is moved horizontally in a gravitational field, what is the work done by gravity?
The work done by gravity is zero when an object is moved horizontally because the displacement is perpendicular to the gravitational force.
If a 2 kg object is lifted to a height of 3 meters, how much work is done against gravity?
a) 58.86 J
b) 19.62 J
c) 29.4 J
d) 6 J
Answer: a) 58.86 J
When an object is dropped from a height, the work done by the gravitational field is:
a) Zero
b) Negative
c) Positive
d) Undefined
Answer: c) Positive
If an object is moved horizontally in a gravitational field, the work done by gravity is:
a) Positive
b) Negative
c) Zero
d) Equal to the weight of the object
c) Zero
Answer:
What happens to the gravitational potential energy of an object when it is lifted?
a) It decreases
b) It remains constant
c) It increases
d) It becomes kinetic energy
Answer: c) It increases
The work done by gravity when an object falls freely is equal to:
a) The increase in kinetic energy
b) The decrease in potential energy
c) Both A and B
d) None of the above
Answer: c) Both A and B