On the earth, an astronaut throws a ball straight upward; it stays in the air for a total time of 2.5 s before reaching the ground again. if a ball were to be thrown upward with the same initial speed on the moon, how much time would pass before it hit the ground? on the earth, an astronaut throws a ball straight upward; it stays in the air for a total time of 2.5 before reaching the ground again. if a ball were to be thrown upward with the same initial speed on the moon, how much time would pass before it hit the ground? 6.1 s 37 s 90 s 15 s

Explanation:

This is a situation related to vertical motion with constant acceleration, where the equation that will be usefull is:

(1)  

Where:  

is the final height of the ball (when it reaches the ground)

is the initial height of the ball (is also zero because is thrown from ground)

is the initial velocity of the ball

is the time the ball is in air (on Earth)

is the acceleration due to gravity  on Earth

is the acceleration due to gravity  on the Moon

Having this clear, let's solve (1) for the Earth:  

(2)  

(3)  

(4)  

(5)  

(6)  This is the initial velocity

Using this same velocity and equation (4) for the Moon:

(7)  

Finally finding :

it takes about 30 days for it to break down

the answer is the first electromagnet (a). this is because it has more coils around the ferromagnetic material. increasing the number of coils increases the surface area in which the metal interacts with the current in the coil. this enables more atoms in the metal to become aligned hence becoming more magnetized.