Answer:
ΔK = -6 10⁴ J
Explanation:
This is a crash problem, let's start by defining a system formed by the two trucks, so that the forces during the crash have been internal and the moment is preserved
initial instant. Before the crash
p₀ = m v₁ + M 0
final instant. Right after the crash
p_f = (m + M) v
p₀ = p_f
mv₁ = (m + M) v
v =
we substitute
v =
3
v = 1.0 m / s
having the initial and final velocities, let's find the kinetic energy
K₀ = ½ m v₁² + 0
K₀ = ½ 20 10³ 3²
K₀ = 9 10⁴ J
K_f = ½ (m + M) v²
K_f = ½ (20 +40) 10³ 1²
K_f = 3 10⁴ J
the change in energy is
ΔK = K_f - K₀
ΔK = (3 - 9) 10⁴
ΔK = -6 10⁴ J
The negative sign indicates that the energy is ranked in another type of energy
Options
a. The worker carried the lunch up to the 53rd floor in the elevator.
b. The worker got a ride in a helicopter to the top of the 68-floor building and then carried the lunch down in the elevator to the 53rd floor?
c. The Worker carried it up the stairs to the 53rd floor.
d. Gravitational potential energy does not depend on the path taken.
Answer:
The gravitational Energy would remain the same in all cases.
Explanation:
Gravitational Energy is a conservative energy and its potential energy comes from gravitational actions.
An instance is when someone lifts a weight from the floor to a certain height and then dropped the weight back to the floor; the work done by the field will not be altered at all; it'll be the same throughout.
If otherwise, it'll be against thermodynamics 2nd law of physics because the object would have remaining energy after returning to the starting point,
For this reason, the gravitational potential energy only depends from the height, and is independent from the path taken to reach there.
A.) All the vector quanties have magnitude(strength) as well as direction. Since force is a vector quantity, it has both strength as well direction.