Question

If the potential energy of the system is zero, the force on the object is zero. When air resistance is taken into account, a ball thrown directly upward spends more time on the way down than on the way up. You drop a ball to the ground from rest, and, from the same height, throw a second identical ball down to the ground. Their change in gravitational potential energies are different. The potential energy of a system can be negative. If the force on an object is zero, the potential energy of the system is zero.

Answer 1

Answer:

Explanation:

Considering it to be True or False Statements

(a)True ,

when Potential Energy of the system is zero then force on the object is zero

$F=-\frac{\mathrm{d} U}{\mathrm{d} x}$

$F=0$

(b)True

When ball is thrown upward it faces air resistance of greater magnitude because of the high speed of ball. while on returning the speed of ball gradually increase therefore it  take more time to reach same spot

(c)True

Change in gravitational Potential Energy of two balls will be different as gravitational Potential Energy depends on the distance of object from datum.

Also Potential Energy can also be negative as it depends on reference

(d)False

if Force on object is zero then Potential Energy is constant not zero

$F=0$

i.e.$\frac{\mathrm{d} U}{\mathrm{d} x}=0$

$U=constant$