An electric heater rated 600 w operates 6 hours per day find the cast to operate it for 30 days , at rs. 4.00 per unit
1 answer:
You might be interested in
Answer:
A) P.E = 138.44 J
B) The velocity of swing at bottom, v = 3.33 m/s
C) The work done, W = -138.44 J
Explanation:
Given,
The mass of the child, m = 25 Kg
The length of the swing rope, L = 2.2 m
The angle of the swing to the vertical position, ∅ = 42°
A) The potential energy at the initial position ∅ = 42° is given by the relation
P.E = mgh joule
Considering h = 0 for the vertical position
The h at ∅ = 42° is h = L (1 - cos∅)
P.E = mgL (1 - cos∅)
Substituting the given values in the above equation
P.E = 25 x 9.8 x 2.2 (1 - cos42°)
= 138.44 J
The potential energy for the child just as she is released, compared to the potential energy at the bottom of the swing is, P.E = 138.44 J
B) The velocity of the swing at the bottom.
At bottom of the swing the P.E is completely transformed into the K.E
∴ K.E = P.E
1/2 mv² = 138.44
1/2 x 25 x v² 138.44
v² = 11.0752
v = 3.33 m/s
The velocity of the swing at the bottom is, v = 3.33 m/s
C) The work done by the tension in the rope from initial position to the bottom
Tension on string, T = Force acting on the swing, F
=
= - 2.2 x 25 x 9.8 [cos0 - cos 42°]
= - 138.44 J
The negative sign in the in energy is that the work done is towards the gravitational force of attraction.
The work done by the tension in the ropes as the child swings from the initial position to the bottom of the swing, W = - 138.44 J
Answer: The correct answer is option B.
Explanation:
Mass of the sled = 10 kg
Initial speed of the sled = 2 m/s
Kinetic energy of the sled =
Work done by the sled = 20 joules
The work done by the friction will be in opposite direction and equal to the magnitude of the work done of the sled that - 20 J.
Hence, correct answer is option B.
Answer:
The answers are located in each of the explanations showed below
Explanation:
a)
(i) Surface Tension: The tensile force that causes this tension acts parallel to the surface and is due to the forces of attraction between the molecules of the liquid. The magnitude of this force per unit of length is called surface tension.
σ = F/l [N/m]
where:
F = force [N]
l = length [m]
σ = Surface Tension [N/m]
(ii) Frequency is the number of repetitions per unit of time of any periodic event.
f = 1/T [1/s] or [s^-1] or [Hz]
where:
T = period [s] or [seconds]
f = frecuency [Hz] or [hertz]
(iii) Each of the units will be shown for each variable
v = velocity [m/s]
a = accelertion [m/s^2]
s = displacement [m]
b) To find the velocity we must derivate the function X with respect to t because this derivate will give us the equation for the velocity, it means:
ii) replacing in the derivated equation.
iii) the average velocity is defined by the expresion v = x/t
2
a) Pascal's principle or Pascal's law, where the pressure exerted on an incompressible fluid and in balance within a container of indeformable walls is transmitted with equal intensity in all directions and at all points of the fluid.
Therefore:
P1 = pressure at point 1.
P2 = pressure at point 2.
P1 = F1/A1
P2= F2/A2
b) One of the applications of the surface tension is the <u>capillarity</u> this is a property of liquids that depends on their surface tension (which, in turn, depends on the cohesion or intermolecular force of the liquid), which gives them the ability to climb or descend through a capillary tube.
Other examples of surface tension:
The mosquitoes that can sit on the water.
A clip on the water.
Some leaves that remain floating on the surface.
Some soaps and detergents on the water.