A1-lb block and a 100-lb block are placed side by side at the top of a frictionless hill. each is given a very light tap to begin their race to the bottom of the hill. in the absence of air resistance, what can you conclude about the outcome of the race?
a)the 1-lb block wins the race. b)the 100-lb block wins the race. c)the two blocks end in a tie. d)there’s not enough information to determine which block wins the race

The answer is c)The two blocks end in a tie

Explanation (See attachment):  

Let´s solve the general problem:

The hill is an inclined plane. We know there is no friction and no air resistance.

Let´s solve by using Energy equations and energy conservation law. At the top of the hill when the block is not moving it has a Potential Energy, as soon as it starts moving, all that Potential Energy starts converting to Kinetic Energy until it reaches the end of the hill:

1) At the top of the inclined plane we have a block of mass "m" with potential energy of , where "m" is mass, "g" is gravity acceleration and "h" is height.

2) Just an instant before the block hits the bottom, it has a Kinetic Energy of where "m" is mass, and "v" is velocity

Thanks to energy conservation law we know that Ep = Ek:

As we can see in our last equation, mass cancels out. This means that mass does not play a role in how fast this object slides down the inclined plane.

In conclusion, it doesn´t matter how much mass or how heavy the block is, it is going to slide down at the exact same velocity in a frictionless slide and without air resistance. This means, a 1lb block and a 100lb block will reach the bottom of the hill at the same time.

weight of the box is given as

here this is placed on the inclined of angle 42 degree

now this weight will have two components one is along the incline other is perpendicular to it

so here we need to apply a force parallel to incline opposite to its component of weight

so here the component of weight is given as

here we have

so it requires 75 n force to move it upwards