6.
if an astronaut were to exert a force on a ball, the ball would

a. fall downward

b. exert a force on the astronaut

c. make the astronaut fall

d. stop

If an astronaut were to exert a force on a ball, the ball would exert a force on the astronaut.

Option B

Explanation:

If an astronaut applies force on the ball, same force will be applied on astronaut. It is universal as also according to Newton’s 3rd law. But, in space, there is no force of gravity. And so, the masses need not be considered.

If he pushes the ball with a force, and it gains some velocity v, the astronaut himself, will attain the same velocity. This is because, in space, no object attracts a mass. Astronaut fall is also correct if he applies a large amount of force while pushing.

if the thermos has a vacuum innner, then heat through conv currents and conduction are reduced = vacuum flask