Answer:
The planets and moons that orbit in the solar system.
Explanation:
For example the earth moves at 67,000 mph (107,000 km/h), and is constant from the gravitational pull of the sun. The moon orbits at about 2,288 mph (3,683 km/h). these are both traveling at different velocities but at a constant speed.
Using the 3rd equation of motion:
= v² - u² = 2gs ------ [g = Acceleration due to gravity]
= v² - 20² = 2 × 10 × 300
= v² - 400 = 6000
= v² = 6000 - 400
= v = √5600
= v = 74.83 m/s
And yeah it's done :)
Electrical energy is used to run the fan
Here as per given condition 750 J of electrical energy is used to run the fan which is converted into Kinetic energy as 400 J
So here we can see that 350 J of energy is lost against many other type of frictional and resistive loses.
So here we can say that out of 750 J of energy only 400 J is used to run the fan and rest amount of energy is lost against friction.
also we can say that efficiency of this fan will be
Compound machines have two or more simple machines
Answer:
Explanation:
Let m be mass of each sphere and θ be angle, string makes with vertex in equilibrium.
Let T be tension in the hanging string
T cosθ = mg ( for balancing in vertical direction )
for balancing in horizontal direction
Tsinθ = F ( F is force of repulsion between two charges sphere)
Dividing the two equations
Tanθ = F / mg
tan17 = F / (7.1 x 10⁻³ x 9.8)
F = 21.27 x 10⁻³ N
if q be charge on each sphere , force of repulsion between the two
F = k q x q / r² ( r is distance between two sphere , r = 2 x .7 x sin17 = .41 m )
21.27 x 10⁻³ = (9 X 10⁹ x q²) / .41²
q² = .3973 x 10⁻¹²
q = .63 x 10⁻⁶ C
no of electrons required = q / charge on a single electron
= .63 x 10⁻⁶ / 1.6 x 10⁻¹⁹
= .39375 x 10¹³
3.9375 x 10¹² .
