The Principles Of Work And Energy: Quiz!

Explanation
The work done on the cart can be calculated by multiplying the force applied to the cart by the distance it is moved. In this case, Mary applies a force of 150N and moves the cart a distance of 10m. Therefore, the work done on the cart is 150N x 10m = 1500 joules.

Explanation
When Nancy pushes an object with twice the force for half the distance, the work done is calculated by multiplying the force applied by the distance covered. Since the force is doubled and the distance is halved, the two changes cancel each other out, resulting in the same amount of work being done. Therefore, Nancy does the same work.

Explanation
When lifting an object, the work done is calculated by multiplying the force applied by the distance over which the force is applied. In this case, the force applied is equal to the weight of the rock, which is given by the formula weight = mass x gravity. The mass of the rock is 10kg and the acceleration due to gravity is approximately 9.8m/s^2. Therefore, the weight of the rock is 10kg x 9.8m/s^2 = 98N. The distance over which the force is applied is 10m. So, the work done is 98N x 10m = 980 joules. Therefore, the correct answer is 1000 joules.

Explanation
Pollution refers to the change in the quality of the environment that is harmful and unpleasant for living things. It includes the release of harmful substances or pollutants into the air, water, or soil, causing damage to ecosystems, human health, and the overall balance of the environment. Pollution can be caused by various sources, such as industrial activities, vehicle emissions, improper waste disposal, and deforestation. It is a significant global issue that requires collective efforts to mitigate and prevent its adverse effects on the environment and living organisms.

Explanation
Potential energy is the correct answer because it refers to the energy that a body possesses due to its position or condition. It is the energy that is stored and can be released or transformed into other forms of energy. This energy is dependent on factors such as height, mass, and gravity, and can be found in various forms such as gravitational potential energy, elastic potential energy, or electrical potential energy.

Explanation
Work is being done only when a force is moving an object. In order for work to be done, there must be a displacement of the object in the direction of the applied force. If the object is stationary, even if a force is applied to it, there is no movement and therefore no work is being done. Thus, the correct answer is "moving".

Explanation
Work is defined as the product of force and displacement. In order for work to be done, the force must cause the object to move a certain distance. The other options, such as "way," "energy," and "temperature," are not directly related to the concept of work in physics. Therefore, the correct answer is "distance."

Explanation
When a force acting on a body displaces it in the direction of the force, work is done. Work is defined as the product of the force applied on an object and the displacement of the object in the direction of the force. In this scenario, since the body is displaced in the direction of the force, there is a transfer of energy from the force to the body, resulting in work being done.

Explanation
Kinetic energy is the energy possessed by a moving object due to its motion. It is directly proportional to the object's mass and the square of its velocity. When an object is in motion, it has the ability to do work or cause a change in its surroundings. Therefore, the correct answer is kinetic energy.

Explanation
A moving car possesses mechanical energy because it is in motion, which is a form of kinetic energy. The car's mechanical energy comes from the conversion of potential energy stored in the car's fuel into kinetic energy as the car moves. This energy is used to overcome friction and other resistive forces, allowing the car to move and perform work. Sound energy is a form of mechanical energy, but it is not directly related to the car's motion. Heat energy and chemical energy may be present in the car's engine, but they are not directly related to the car's motion.