Question

Answer Q.No.7(a) -7(d) on the basis of of your understanding of the following paragraph and

the related studies concepts: 4

Rashmi had a bad experience during the take off the plane when she boarded it for the first time.

Her friend assisted and helped her to fasten the seat belt. She explained to her about free fall that

whenever an object falls towards the earth, the acceleration involved due to its gravitational pull

is called acceleration due to gravity.

7(a). What is free fall?

7(b). Why do we tie our seat belts during landing / take off the plane?

7(c). The astronauts in space weight less Why?

7(d). What is the final velocity when a body is dropped from a height?

Science Class 9 ​

Answer 1

Answer:

free fall means the object is falling under the action of gravity.

we tie seat belts because to protect us from injury.

the astronauts in space are weightless because there is no availability of gravity.

final belocity will be zero

Answer 2

(a)

free fall

In Newtonian physics, free fall is defined as the motion of an object where gravity is the only force acting upon it.

(b)

Seat belts stop you tumbling around inside the plane if there is a collision. Upon sensing a collision the seat belts lock in place. When the plane crashes, there is no unbalanced force acting on the person, so they continue forward (Newton's First Law). The person moves against the seat belt, exerting a force on it. The seat belt then exerts a force back on the person (Newton's Third Law). This causes a controlled deceleration of the person.

(c)

a. there is no gravity in space and they do not weigh anything.

b. space is a vacuum and there is no gravity in a vacuum.

c. space is a vacuum and there is no air resistance in a vacuum.

d. the astronauts are far from Earth's surface at a location where gravitation has a minimal effect

(d)

zero