# Newton's third law of motion help

• jehan4141
In summary, according to Newton's laws of motion, the correct answer is E - none of the above is true according to the third law. This is because in all of the scenarios given, there is not an equal and opposite force being exerted, which is a key principle of Newton's 3rd law. For example, in scenario D, the astronauts throwing a ball back and forth, although the distance between them remains constant, the force exerted on the ball is not equal and opposite to the force exerted on the astronauts. Therefore, the distance between them will not increase due to a force between the catcher and thrower, but rather due to the force exerted on the ball.

#### jehan4141

Hello! My question is about Newton's 3rd law:

Which one of the following is true, according to Newton's laws of motion? Ignore friction.

a. an SUV hits a stationary motorcycle. Since it is stationary, the motorcycle sustains a greater force than the SUV does
b. a semitrailer truck crashes all the way through a wall. since the wall collapses, the wall sustains a greater force than the truck does.
c. sam (18 years old) and his sister (9 years old) go ice skating. they push off against each other and fly apart. sam flies off with greater acceleration.
d. two astronauts on a space walk are throwing a ball back and forth ebtween each other. in this game of catch the distance ebtween them remains constant
e. none of the above is true, according to the third law.

I know that the answer is E, that none of the above is true, but I do not understand what D is saying. How does E apply to the third law?

Thank you so much in advance! :)

Ohhh okay I think I may have gotten it. Is it because as you throw a ball, you exert a force on the ball, in the direction of the catcher. Thus, there's an equal and opposite force placed upon you (the thrower). So you are propelled further and further from the other person (the catcher)?

In throwing and catching the ball, you exert a force on the ball. Because of the opposite force from the ball, the distance will increase (not because of a force between the catcher and thrower)

Thank you! )