When you climb, earth exerts gravitational force on pack in downward direction(pointing towards the center of earth).
In order to climb, you need to work against work done by gravity on the pack.
Hence work done by you = work done by gravity on pack
= Force x displacement = 70 x 30 = 2100 J.
So you need to do 2100 joules of work to lift your pack.
Power is the rate of work done.
Therefore power = work done by you/time(in seconds)
= 2100/600 =3.5 watts
Answer:
The common velocity v after collision is 2.8m/s²
Explanation:
look at the attachment above ☝️
Answer:
1.7 seconds
Explanation:
To clear the intersection, the total distance to be covered = 59.7 + 25 =84.7m
first we need to find the initial speed to just enter the intersection by using the third equation of motion
v^2 - u^2 = 2*a*s
45^2 - u^2 = 2 * -5.7 * 84.7
u^2 = 45^2 +965.58
u^2 = 2990.58
u = 54.7 m/s
Now for time we apply the first equation of motion
v-u =a * t
t = (v-u)/a = (45 - 54.7)/-5.7 = 1.7seconds
Do 112m /29s which it will be 3.862 which if you round it, it will be 3.86 m/s
Answer:
853776 J
Explanation:
The work-energy needs to pump water out of the pool is the product of the weight of water and distance h
E = Wh = mgh
Since water mass is a body of water we can treat it as the product of density 1000kg/m3 and volume, which is the product of base area and uniform height h
Therefore:
![E = mgh = g\rho A\int\limits^{2.2}_0 {h} \, dh\\E = 9.8*1000*30*12[h^2/2]^{2.2}_0 = 1764000(2.2^2 - 0^2) = 853776 J](https://tex.z-dn.net/?f=E%20%3D%20mgh%20%3D%20g%5Crho%20A%5Cint%5Climits%5E%7B2.2%7D_0%20%7Bh%7D%20%5C%2C%20dh%5C%5CE%20%3D%209.8%2A1000%2A30%2A12%5Bh%5E2%2F2%5D%5E%7B2.2%7D_0%20%3D%201764000%282.2%5E2%20-%200%5E2%29%20%3D%20853776%20J)
