The height of the ball above the ground is 38.45 m
First we will calculate the velocity of the ball when it touch the ground by using first equation of motion
v=u+gt
v=0+9.81×2.8
v=27.468 m/s
now the height of the ground can be calculated by the formula
v=√2gh
27.468=√2×9.81×h
h=38.45 m
Answer:
b) 5 J
Explanation:
Work is the energy transferred by an object when acted by a force along a displacement. Work is the product of force and displacement. The SI unit of work is the joules (J)
To calculate the work done by the force, we have to first get the displacement (D) of the object. Hence:
Displacement (D) = Q(3, 8) - P(1, 3) = (3 - 1, 8 - 3) = (2, 5) = 2i + 5j
The work done is the dot product of the force and the displacement. Force = 5i - j. Hence:
Work done = (5i - j)(2i + 5j) = 10 - 5 = 5 J
<span>the easy walk harness should be looser on the dog than other harnesses</span>
False, as an object falls its potential energy turns into kinetic energy thus decreasing the potential energy.
Answer:
time required is 6.72 years
Explanation:
Given data
mass m = 3.20 ✕ 10^7 kg
height h = 2.00 km = 2 × 10^3 m
power p = 2.96 kW =2.96 × 10^3 J/s
to find out
time period
solution
we know work is mass × gravity force × height
and power is work / time
so we say that power = mass gravity force × height / time
now put all value and find time period
power = mass × gravity force × height / time
2.96 × 10^3 = 3.20 ✕ 10^7 × 9.81× 2 × 10^3 / time
time = 62.784 × 10^10 / 2.96 × 10^3
time = 21.21081081 × 10^7 sec
time = 58.91891892 × 10^3 hours
time = 6.72 years
so time required is 6.72 years
