Answer:
0.5sec
Explanation:
Parameters
Height(H) =20m
Initial velocity(u) = 5m/s
Acceleration due to gravity(g) =10m/s^2
Method one
Using the second law of motion
H=ut-1/2gt^2
20=5t-1/2×10×t^2
20=5t-5t^2
dh/dt = 5-10t
where any constant is zero therefore the 20 is zero
5-10t=0
Collect like terms
-10t= -5
t=1/2 = 0.5sec
2nd method
Parameters
Height(H) =20m
Initial velocity(u) = 5m/s
Acceleration due to gravity(g) =10m/s^2
Using the time taken formula
t=u/g
t=5/10
t=0.5sec
Answer:
The rate of change of an object's velocity is called acceleration.
Answer:
A. 2.41 s.
B. 24.3 m/s.
Explanation:
vf = vi + 2a*t
where, vf = final velocity
= 0 m/s
vi = final velocity
= 1.5 m/s
a = 9.8 m/s^2
A.
ti = 1.5/(9.8 * 2)
= 0.08 s
Vf^2 = Vi^2 + 2a*s
1.5^2 = 2 * 9.8 * s
S = 0.115 m
Time taken to drop into the water,
30.115 = 1.5*to + 4.9*to^2
to = 2.33 s
Total time taken = ti + to
= 2.33 + 0.08
= 2.41 s.
B.
Vo = 0 m/s
S = 30.115 m
Vf = ?
Using,
Vf^2 = Vo^2 + 2*a*s
= sqrt (2*9.8*30.115)
= 24.3 m/s.
Answer:
A. 70 Ns
B. 70 Kgm/s
C. 2.19 m/s
Explanation:
A. Determination of the impulse.
Force (F) = 20 N
Time (t) = 3.5 s
Impulse (I) =?
Impulse (I) = force (F) × time (t)
I = Ft
I = 20 × 3.5
I = 70 Ns
Thus, the Impulse is 70 Ns.
B. Determination of the change in momentum
Force (F) = 20 N
Time (t) = 3.5 s
Change in momentum =?
Change in momentum = m(v – u) = Ft
Change in momentum = Ft
Change in momentum = 20 × 3.5
Change in momentum = 70 Kgm/s
C. Determination of the final velocity.
Change in momentum = 70 Kgm/s
Initial velocity (u) = 0 m/s
Combined mass (m) = 32 kg
Final velocity (v) =?
Change in momentum = m(v – u)
70 = 32(v – 0)
70 = 32(v)
70 = 32v
Divide both side by 32
v = 70 / 32
v = 2.19 m/s
Thus, the final velocity is 2.19 m/s
Answer: B. Its randomness would increase
Explanation:
According to the <u>second law of thermodynamics</u>:
<em>"The amount of entropy in the universe tends to increase over time"</em>
<em />
That is, in any cyclic process, entropy will increase, or remain the same.
So, in this context, entropy is a thermodynamic quantity defined as a criterion to predict the evolution or transformation of thermodynamic systems. In addition, it is used to measure the degree of organization of a system.
In other words: Entropy is the measure of the disorder (or randomness) of a system and is a function of state.
