NCERT Solutions For Class 8 Science Chapter 8 Force And Pressure LAQs
Question 1. In walking, the pressure on the ground is greater than that in standing on the ground. Explain this statement.
Answer: When a person is walking on the ground, at one time, one foot is only on the ground. Therefore, the entire weight of a man falls on a smaller area of the ground, which results in a large pressure on the ground. While in another case, if the man is standing on the ground, then both his feet are on the ground. It causes the force of weight of a man to fall on a larger area of ground and results in less pressure on the ground.
NCERT Solutions for Class 8 Science Force and Pressure
Question 2. Two women are of the same weight. One wears sandals with pointed heels while the other wears sandals with flat soles. Which one would feel more comfortable while walking on a sandy beach? Give reasons for your answer.
Answer:
While walking on a sandy surface, one needs footwear larger area so that the pressure exerted on the ground is minimal. So, in this case, the woman having the sandals with pointed heels will be less comfortable while walking, while the other woman wears sandals with flat soles, feels more comfortable while walking on a sandy beach.
Question 3. It is difficult to cut cloth using a pair of scissors with blunt blades. Explain.
Answer:
It is difficult to cut cloth using a pair of scissors with blunt blades because blunt blades have more area, and due to this, the applied force produces very little pressure. As we know that pressure is inversely proportional to the area of cross-section, so it is difficult to cut cloth with blunt blades
⇒ (\(p=\frac{F}{A}\))
NCERT Solutions for Force and Pressure Chapter 8
Question 4. Observe the vessels A, B, C, and D as shown in the figure carefully.
The volume of water taken in each vessel is as shown. Arrange them in the order of decreasing pressure at the base of each vessel. Explain.
Answer:
- Pressure at depth due to the liquid column depends upon
- Gravitational acceleration
- Density of liquid
- Height of liquid.
And in this case, gravitational acceleration and density are the same, so the only thing that can change pressure is height.
NCERT Class 8 Science Chapter 8 Force and Pressure Solutions
So, the order of pressure exerted by the fluids A, B, C, and D at the base is given by
PD> PB > PA > PC
Question 5. An archer shoots an arrow in the air horizontally. However, after moving some distance, the arrow falls to the ground. Name the initial force that sets the arrow in motion. Explain why the arrow ultimately falls.
Answer:
The archer shoots an arrow by applying muscular force by stretching the string of the bow. When the string is released, it regains its original position that provides the initial force to set the arrow in motion horizontally. The force of gravity acts on the arrow in the downward direction, and hence the arrow ultimately falls to the ground.