When Do Two Vertically Thrown Balls Meet?

[shikagami]

1. A ball A is thrown vertically upwards from the ground at a velocity of 20 m/s. A second identical ball is thrown vertically upwards, at the same velocity, one second later from a platform 10 meters above the ground. The two balls will be at the same height above ground when ...

a. A is traveling upwards and B is traveling downwards.
b. A is traveling downwards and B is traveling upwards.
c. A is traveling upwards and B is also traveling upwards.
d. A has reached its maximum height.

2. Two satellites, S1 and S2, are orbiting a planet. S1 has a mass of m and an orbiting radius of r. S2 has a mass of 2m and an orbiting radius of 2r. What is the ratio of the force of S2 to that on S1?

a. 4:1
b. 2:1
c. 1:2
d. 1/4:1

Please help

 

[OlderDan]

1. A ball A is thrown vertically upwards from the ground at a velocity of 20 m/s. A second identical ball is thrown vertically upwards, at the same velocity, one second later from a platform 10 meters above the ground. The two balls will be at the same height above ground when ...

a. A is traveling upwards and B is traveling downwards.
b. A is traveling downwards and B is traveling upwards.
c. A is traveling upwards and B is also traveling upwards.
d. A has reached its maximum height.

2. Two satellites, S1 and S2, are orbiting a planet. S1 has a mass of m and an orbiting radius of r. S2 has a mass of 2m and an orbiting radius of 2r. What is the ratio of the force of S2 to that on S1?

a. 4:1
b. 2:1
c. 1:2
d. 1/4:1

Please help

Show us an attempt to solve these, and then ask for some help

 

[thepatientmental]

me with this question.

1. The correct answer is b. A is traveling downwards and B is traveling upwards. This is because both balls have the same initial velocity and are affected by gravity in the same way, so the ball thrown from the higher platform will take longer to reach the ground and will be traveling upwards when the first ball is already on its way down.

2. The correct answer is b. 2:1. According to Newton's Law of Universal Gravitation, the force between two objects is directly proportional to the product of their masses and inversely proportional to the square of the distance between them. In this case, both satellites have the same distance from the planet, but S2 has twice the mass of S1, resulting in a force that is twice as strong. Therefore, the ratio of the force on S2 to that on S1 is 2:1.