The answer is 117.6 J
The potential energy of
the object is actually its stored energy:
<span>E =
m · g · h
E - the potential energy of the object,
m - the mass of the object,
g - acceleration due to gravity,
h - the height of the object.
m = 4 kg
g = 9.8 m/s</span>²
h = 3 m
E = 4 * 9.8 * 3 = 117.6 J
They can be described as small in quantity and very dangerously radioactive.
Acceleration = velocity / time.
First, we will get the resultant force:
The direction of the force due to the person's weight is vertically down.
weight of person = 700 newton
Assume that the force exerted by the arms has a vertically upwards direction.
Force exerted by arms = 2*355 = 710 newtons
Therefore, the resultant force = 710 - 700 = 10 newtons (in the vertically upwards direction)
Now, we will get the mass of the person.
weight = 700 newtons
weight = mass * acceleration due to gravity
700 = 9.8*mass
mass = 71.428 kg
Then we will calculate the acceleration of the resultant force:
Force = mass*acceleration
10 = 71.428*acceleration
acceleration = 0.14 m/sec^2
Finally, we will use the equation of motion to get the final speed of the person.
V^2 = U^2 + 2aS where:
V is the final velocity that we need to calculate
U is the initial velocity = 0 m/sec (person starts at rest)
a is the person's acceleration = 0.14 m/sec^2
S is the distance covered = 25 cm = 0.25 meters
Substitute with the givens in the above equation to get the final speed as follows:
V^2 = U^2 + 2aS
V^2 = (0)^2 + 2(0.14)(0.25)
V^2 = 0.07
V = 0.2645 m/sec
Based on the above calculations:
The person's speed at the given point is 0.2645 m/sec
671mi/hr
= 671/60min (calculates miles/min)
= (671/60) ÷ 60seconds (calculates miles/sec)
((671/60) ÷ 60)× 1609m
= 299.899 meters/sec
= 299.90m (round off to 2 decimals )