Answer:
The question does not state how the answer is to be entered. I would use 10% because that is most common.
Explanation:
You are using 300 J of energy to get 30 J of light energy. The fact that you can account for the left over energy is not relevant.
Efficiency = Work Out / Work In
Efficiency = 30 J / 300 J = 0.1
If you need this as a %, you can multiply by 100
Efficiency = 0.1 * 100 = 10%
The formula for potential energy is mass x height x gravitational force. Your mass is 5.3 kg and your height is 6.6 meters. The gravitational force on earth is 9.8 m/s. That means your answer is 5.3 x 6.6 x 9.8 and that equals 342.804
Answer:
option (a)
Explanation:
The magnetic field is produced by the electric current, and the direction of magnetic field is given by the Maxwells' right hand rule.
The magnetic field is also be produced by the time varying magnetic fields.
Answer:
The length of her shadow is changing at the rate -2 m/s
Explanation:
Let the height oh the street light, h = 22 ft
Let the height of the woman, w = 5.5 ft
Horizontal distance to the street light = l
length of shadow = x
h/w = (l + x)/x
22/5.5 = (l + x)/x
4x = l + x
3x = l
x = 1/3 l
taking the derivative with respect to t of both sides
dx/dt = 1/3 dl/dt
dl/dt = -6 ft/sec ( since the woman is walking towards the street light, the value of l is decreasing with time)
dx/dt = 1/3 * (-6)
dx/dt = -2 m/s
Answer:
K = ½ kg m2 / s2
Explanation:
The kinetic energy rotation is given by the expression
K = ½ I w²
Where I is the moment of inertia and w is the angular velocity.
We have a relationship between linear and angular velocity
v = w r
Where r the distance from the point of rotation, in this case it is the point or where the ball is, so the linear velocity is the same as the ball.
w = v / r
We replace
K = ½ I (v / r)²
Let's calculate
K = ½ kg m2 )(m/s )/ m) 2
K = ½ kg m2 / s2
