Answer:
false statement : b ) For the motion of a cart on an incline plane having a coefficient of kinetic friction of 0.5, the magnitude of the change in kinetic energy equals the magnitude of the change in gravitational potential energy
Explanation:
mechanical energy = potential energy + kinetic energy = constant
differentiating both side
Δ potential energy + Δ kinetic energy = 0
Δ potential energy = - Δ kinetic energy
first statement is true.
Friction is a non conservative force so inter-conversion of potential and kinetic energy is not possible in that case. In case of second option, the correct relation is as follows
change in gravitational potential energy = change in kinetic energy + work done against friction .
So given 2 nd option is incorrect.
In case of no change in gravitational energy , work done is equal to
change in kinetic energy.
Answer:
The Doppler red-shift of light observed from distant stars and galaxies gives evidence that the universe is expanding (moving away from a central point). This allows for Big Bang Theory, because after a “bang” occurs all of the matter moves away from the point of origin.
Pressure is the force applied perpendicular to a surface divided by the area of the surface. Therefore, from the given values, we can easily calculate the area by dividing the force to the pressure. We do as follows:
Area = F / P
Area = 15000 / 190000
Area = 0.0789 m^2
Hope this answers the question. Have a nice day.
