Answer:
d. The hammer falls with a constant acceleration
Explanation:
Since gravity is the only thing that is acting on the hammer as it falls and gravity is a form of acceleration then acceleration of 9.81m/s² which is gravity is the correct answer.
Answer:
B
Explanation:
From Newton's law of motion, we have:
V^2 = U^2 + 2gH
Where V and U are final and initial velocity respectively.
H is the height.
For the object to have a sustain a maximum height it means the final velocity of the object is zero.
By computing the height of the object sustain by A, we have:
0^2 = 2^2 -2×10×H
0= 4 -20H
4 = 20H;
H= 0.2m
For object B we have;
0^2 = 1^2 -2×10×H
0 = 1 -20H
H = 1/20= 0.05m
From computing the height sustain by both objects, we see object B is projected at a shorter height into atmosphere than A.
Hence object B will return to the ground first.
Answer:
t = 2.97[s]
Explanation:
To solve this problem we must use the following kinematics equations, we must bear in mind that the positive sign of the acceleration value means that the car is increased its speed.
where:
x - xo = 180 [ft]
a = acceleration [ft/s^2]
Vo = initial velocity = 53 [ft/s]
Vf = final velocity = 68 [ft/s]
Now replacing we find:
(68^2) = (53^2) + (2*a*180)
a = 5.04 [ft/s^2]
Now using the following equation:
68 = 53 + (5.04*t)
t = (68 - 53)/5.04
t = 2.97[s]
The statements supported are:
- The usable energy in the universe is decreasing.
- The entropy of the universe is increasing.
The second law of Thermodynamics establishes that in each energy convertion, in an isolate system, a part of energy is converted into heat (unusable energy) and the entropy of the system increase.