<span>When a person lifts the block, the block has more potential energy. Therefore the person does positive work on the block.
work = m g h
work = (4.5 kg) (9.80 m/s^2) (1.2 m)
work = 52.92 joules
The person's work on the block is 52.92 joules
When the block is being raised, the force of gravity opposes the motion. Therefore the force of gravity does negative work on the block.
work = - (force) (h)
work = - m g h
work = -(4.5 kg) (9.80 m/s^2) (1.2 m)
work = -52.92 joules
The work done by the force of gravity on the block is -52.92 joules
Note that when the block is moved horizontally, the potential energy does not change. Therefore there is no work done on the block when it moves horizontally (we are assuming that the kinetic energy does not change).</span>
Answer:
She will make the jump.
Explanation:
We have equation of motion , , s is the displacement, u is the initial velocity, a is the acceleration and t is the time.
First we will consider horizontal motion of stunt women
Displacement = 77 m, Initial velocity = 28 cos 15 = 27.05 m/s, acceleration = 0
Substituting
So she will cover 77 m in 2.85 seconds
Now considering vertical motion, up direction as positive
Initial velocity = 28 sin 15 = 7.25 m/s, acceleration =acceleration due to gravity = -9.8 , time = 2.85
Substituting
So at time 2.85 stunt women is 10.11 m below from starting position, far side is 25 m lower. So she will be at higher position.
So she will make the jump.
Answer:
d= 794.4 cmExplanation:
Given that
Speed ,V= 286 km/h
V=79.44 m/s
Given that time ,t= 100 ms
t= 0.1 s
We know that ( if acceleration is zero)
Distance = Speed x time
d= V t
Now by putting the values in the above equation
d = 79.44 x 0.1 m
d= 7.944 m
We know that 1 m = 100 cm
d= 794.4 cm