The same constant force is used to accelerate two carts of the same mass, initially at rest, on horizontal frictionless tracks. the force is applied to cart a for twice as long a time as it is applied to cart b. the work the force does on a is wa; that on b is wb. which statement is correct?
a. wa = wb.
b. wa = wb.
c. wa = 2 wb.
d. wa = 4 wb.
e. wb = 2 wa

Explanation:

The work done by a constant force is given by:

In this case the movement is completetly horizontal so:

This reduces the equation to:

Where:

The distance d is given by:

Now, with this in mind, for car A:

Isolating F1:

For car B

Isolating F2:

According to the problem, we know that:

Therefore, matching F1 and F2, and replacing t1 by 2t2:

Multiplying by t2 and v to both sides:

Finally multiplying by 2 to both sides:

hi there!

out of the two, (b) precision would be more reasonable.   however, both a and b could be pretty reasonable.

-awesomerepublic   : )

multiple allele inheritance is traits controlled by more than 2 alleles (ex: pigeons having 3 alleles of one gene govern their feather color).