Force , F = ma
F = m(v - u)/t
Where m = mass in kg, v= final velocity in m/s, u = initial velocity in m/s
t = time, Force is in Newton.
m= 1.2*10³ kg, u = 10 m/s, v = 20 m/s, t = 5s
F = 1.2*10³(20 - 10)/5
F = 2.4*10³ N = 2400 N
The answer would be B..
Since sand can heat up quickly, it will also cool off quickly. But water takes a long time to heat up and cool down.
A booklet is a small book—with fewer pages and smaller dimensions than a “real” book, and usually a paper cover.
Answer:
Part(a): The frequency is
.
Part(b): The speed of the wave is
.
Explanation:
Given:
The distance between the crests of the wave,
.
The time required for the wave to laps against the pier, 
The distance between any two crests of a wave is known as the wavelength of the wave. So the wavelength of the wave is
.
Also, the time required for the wave for each laps is the time period of oscillation and it is given by
.
Part(a):
The relation between the frequency and time period is given by

Substituting the value of
in equation (1), we have

Part(b):
The relation between the velocity of a wave to its frequency is given by

Substituting the value of
and
in equation (2), we have

Answer:
23.0 s
Explanation:
Given:
v₀ = 0 m/s
v = 19.8 m/s
a = 4.80 m/s²
Find: Δx and t
v² = v₀² + 2aΔx
(19.8 m/s)² = (0 m/s)² + 2 (4.80 m/s²) Δx
Δx = 40.84 m
v = at + v₀
19.8 m/s = (4.80 m/s²) t + 0 m/s
t = 4.125 s
The elevator takes 40.84 m and 4.125 s to accelerate, and therefore also 40.84 m and 4.125 s to decelerate.
That leaves 291.3 m to travel at top speed. The time it takes is:
291.3 m / (19.8 m/s) = 14.71 s
The total time is 4.125 s + 14.71 s + 4.125 s = 23.0 s.