Answer:
Impulse will be 12 kgm/sec
So option (b) will be correct option
Explanation:
We have given mass of the baseball m = 0.15 kg
Ball speed before hit 
Ball speed after hitting
( negative direction due to opposite direction )
We have to find the impulse
We know that impulse is equal; to the change in momentum
So change in momentum = 
So option (b) will be correct option
Answer:
It requires more tension to pull up the track
Explanation:
Net force must be zero to maintain constant velocity.
Weight force will always be pointed down the slope. Call it W
Friction force (Call it Ff) will be down slope when movement is up slope.
Friction force will be up slope when movement is down slope.
W and Ff are always positive numbers
Call the pulling force T
If Up slope is considered the positive direction
Moving up slope
Tu - Ff - W = 0
Tu = Ff + W
Moving down slope
Td + W - Ff = 0
Td = Ff - W
Ff + W > Ff - W therefore Tu > Td
Answer:
If the mass of one of the objects is tripled, then the force of gravity between them is tripled. ... Since gravitational force is inversely proportional to the square of the separation distance between the two interacting objects, more separation distance will result in weaker gravitational forces
It can't be pinned down to a single year because scientific work takes place over many years of research and discovery.