It's either staying there or is going at the same pace
Answer:
Explanation:
a )
We shall apply the concept of impulse .
Impulse = force x time = change in momentum
= 5 x 4 = 2 ( V - 3 ) , where V is final velocity of the object
20 = 2V - 6
V = 13 m /s
b )
Impulse applied = - 7 x 4 = - 28 kg m/s ( negative as direction of force is opposite motion )
If v be the final velocity
2 x 3 - 28 = 2 v ( initial momentum - change in momentum = final momentum )
- 22 = 2v
v = - 11 m /s
object will move with 11 m /s in opposite direction .
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.
Answer:
Q = 114895 J
Explanation:
To find the thermal energy gained by the ice you use the following formula:

m: mass of the ice = 0.250kg
T2: final temperature = 22°C
T1: initial temperature = -8.0°C
Hf: heat of fusion of water = 3.34*10^5 J/kg
c: specific heat of water = 4186 J/kg
By replacing the values of the parameters you have:

where you have considered that ice melts completely