1) 14g
2) 24 fl oz
3)10 cups
4)12 and 1/2 cups
Answer:
a. negative
b. zero
Explanation:
work is the change in the energy of a system due to external forces
work is done when a force moves a load through a distance in the direction of the force
The work done by a force on a system is positive when the force and the force displacement point in the same direction and negative when they point in opposite directions
in the scenario we are considering in the question, the force (the hand) moves the block vertically upwards but the displacement of the block reduces (in the opposite direction) since it decelerates. as such the work done by gravity on the block is negative.
the work done on the block is zero if the system consists of the block and the earth because there is no gravitational force exerted on the system
Answer: B
The forklift is doing positive work on the object because the direction of force and the direction of motion are the same. The force of gravity is doing negative work on the object because it is acting opposite to the direction of motion.
Explanation: The work done in lifting an object up is positive when the direction of the displacement and the force applied are in the same direction.
The work will be negative if force and direction of the motion are opposite to each other.
Also, force of gravity is considered positive when an object is moving toward the gravity. That is coming downward. Otherwise, it's negative when it's moving in the opposite direction.
When a forklift raises an object, the forklift is doing positive work on the object because the direction of force and the direction of motion are the same. The force of gravity is doing negative work on the object because it is acting opposite to the direction of motion.
