Question

You have just landed on planet x. you take out a 250-g ball, release it from rest from a height of 12.0 m, and measure that it takes 2.4 s to reach the ground. you can ignore any force on the ball from the atmosphere of the planet. how much does the 250-g ball weigh on the surface of planet x? 104.16667 incorrect: your answer is incorrect. n

Answer 1

I believe your answer is off by a couple of decimal points. The answer is approximately 1.041 N

Answer 2

For the first step, since we know the time it takes to fall 12 meters, 
we can calculate the acceleration of gravity on Planet-X. 

           Falling distance = (1/2) (gravity) (time²)

                            (12 m)  =  (1/2) (gravity) (2.4 seconds)²

                                        =   (1/2 gravity)  (5.76 seconds²)

Divide each side by  (5.76 s²) :

                       1/2 gravity  =  (12 m) / (5.76 s²)

                             gravity  =  (24 m) / (5.76 s²)

                           Gravity  =  4.17 m/s²     (42.5% of Earth gravity)

Now that we know the acceleration  of gravity on Planet-X,
we can calculate the weight of the ball, (or of any mass).

           Weight of any mass = (mass) x (gravity)

For the ball,     Weight = (0.250 kg) x (4.17 m/s²)

                                    =   1.042 Newton

(The same 250-gram ball would weigh 2.45 newtons on Earth.)