Answer: 2000 watts
Explanation:
Given that,
power = ?
Weight of object = 200-N
height = 4 m
Time = 4 s
Power is the rate of work done per unit time i.e Power is simply obtained by dividing work by time. Its unit is watts.
i.e Power = work / time
(since work = force x distance, and weight is the force acting on the object due to gravity)
Then, Power = (weight x distance) / time
Power = (200N x 4m) / 4s
Power = 8000Nm / 4s
Power = 2000 watts
Thus, 2000 watts of power is needed to lift the object.
Answer:
v = 8.09 m/s
Explanation:
For this exercise we use that the work done by the friction force plus the potential energy equals the change in the body's energy.
Let's calculate the energy
starting point. Higher
Em₀ = U = m gh
final point. To go down the slope
Em_f = K = ½ m v²
The work of the friction force is
W = fr L cos 180
to find the friction force let's use Newton's second law
Axis y
N - W_y = 0
N = W_y
X axis
Wₓ - fr = ma
let's use trigonometry
sin θ = y / L
sin θ = 11/110 = 0.1
θ = sin⁻¹ 0.1
θ = 5.74º
sin 5.74 = Wₓ / W
cos 5.74 = W_y / W
Wₓ = W sin 5.74
W_y = W cos 5.74
the formula for the friction force is
fr = μ N
fr = μ W cos θ
Work is friction force is
W_fr = - μ W L cos θ
Let's use the relationship of work with energy
W + ΔU = ΔK
-μ mg L cos 5.74 + (mgh - 0) = 0 - ½ m v²
v² = - 2 μ g L cos 5.74 +2 (gh)
v² = 2gh - 2 μ gL cos 5.74
let's calculate
v² = 2 9.8 11 - 2 0.07 9.8 110 cos 5.74
v² = 215.6 -150.16
v = √65.44
v = 8.09 m/s
Speed = (acceleration) x (time)
Velocity = (speed) in (direction of the speed)
Speed = (-3 m/s²) x (5 s) = 15 m/s
Velocity =
(15 m/s) in the direction opposite to the direction you call positive.
Displacement = (distance between start-point and end-point)
in the direction from start-point to end-point.
Distance = (1/2) (acceleration) (time)²
Distance = (1/2) (3 m/s²) (5 s)²
= (1/2) (3 m/s²) (25 s²) = 37.5 meters
Displacement =
37.5 meters in the direction opposite to the direction you call positive.
The circulatory system is important in meeting the needs of all cells in the body because it offers means of transport by which cells obtain the materials needed to live and function.
The functions of the circulatory system by which the cells are supported include:
1. Respiration- oxygen is delivered to the cells and carbon dioxide is removed from them.
2. Nutrition- nutrients for energy are supplied to every cell in the body.
3. Waste removal- metabolic waste products are taken away before they accumulate and become harmful to the cells.
4. Cellular communication- hormones are transported to the cells and organs that need them for proper functioning.
5.Thermoregulation- As blood circulates, it keeps body temperature balanced and thus cells are able to carry out processes well.
