When is the work done by a force on a body: (a) positive, (b) neg… - Vidyadip

Question

When is the work done by a force on a body: $(a)$ positive, $(b)$ negative, and $(c)$ zero?

✓

Answer

Work done by a force applied on a body is:

Positive work: Positive when the force acts in the direction of motion of the body.
Negative work: Negative when the force acts in the direction opposite to the direction of motion of the body.
Zero work: Zero when the force acts at right angle to the direction of motion of the body.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "Que-Ans (Each of 3 Mark )" from Work and Energy→Work and Energy — all question types→Science STD 9 question papers→Gujarat Board STD 9 question papers→Gujarat Board question paper generator→

Similar questions

A object having a mass $2 \ kg$ and moving at $14 m / s$ collides with another object of mass $5 \ kg$ at rest and sticks to it. Find the speed of this combination.

Why does a desert cooler cool better on a hot dry day?

For proper storage of grains what measures can be adopted?

The scientists now say that there are actually five states of matter $A, B, C, D$ and $E$. The state A has a fixed volume but no fixed shape. The state B can be compressed very easily by applying pressure and state $C$ has a fixed shape as well as a fixed volume. The state $D$ is mixture of free electrons and ions whereas state E is named after an Indian scientist and a famous physicist.

Name the physical states $(i) A\ (ii) B\ (iii) C\ (iv) D$, and $(v) E$.
Name one substance belonging to state $C$ which can directly change into vapours on heating. What is this process known as?
Name one substance which normally belongs to state B but whose solid form changes directly into gaseous state.
Name the most common substance belonging to state $A$.
Which state of matter makes the sum and other stars to glow.

Describe the biological method of weed control.

You are provided with soda water, milk and muddy water. How can you differentiate between them in terms of:

Homogeneity.
Filtration.
Tyndall effect.

In response to a question, a student stated that in an atom, the number of protons is greater than the number of neutrons, which in turn is greater than the number of electrons. Do you agree with the statement? Justify your answer.

Calculate the acceleration due to gravity on the surface of a satellite having a mass of $7.4 \times 10^{22}kg$ and a radius of $1.74 \times 10^6m (G = 6.7 \times 10^{-11}Nm^2/kg^2)$. Which satellite do you think it could be?

What is prokaryotic cell? Differentiate between prokaryotic cell & eukaryotic cell?

Derive the formula: v = u + at, where the symbols have usual meanings.