A girl of mass 40 kg climbs up a rope through a height of 6 m in 16 s. The power expended by her is ______. (Take \(g = -10\text{ m/s}^2\))
To find the power expended by the girl, we need to calculate the work done against gravity and then divide it by the time taken.
Calculating Work Done Against Gravity
The work done (\(W\)) is calculated using the formula:
\(W = m \times g \times h\)
Where:
- \(m\) = mass = 40 kg
- \(g\) = acceleration due to gravity = 10 m/s² (We use the magnitude for work calculation)
- \(h\) = height = 6 m
Substituting the values:
\(W = 40 \text{ kg} \times 10 \text{ m/s}^2 \times 6 \text{ m}\)
\(W = 2400 \text{ Joules}\)
Calculating Power Expended
Power (\(P\)) is the rate at which work is done, calculated as:
\(P = \frac{W}{t}\)
Where:
- \(W\) = Work done = 2400 J
- \(t\) = time = 16 s
Substituting the values:
\(P = \frac{2400 \text{ J}}{16 \text{ s}}\)
\(P = 150 \text{ W}\)
Therefore, the power expended by the girl is 150 W.
Similar Questions
- ______ is defined as the time rate at which work is done or energy is transferred.
- When one joule of energy is consumed in one second, then the power used is said to be?
Which of the following is an INCORRECT formula for power?
The Work done by the motor per unit time is called _________________.
Important Questions from Power
Express the power dissipated in a 100 Ω resistor in dB relative to 1 mW, when the voltage across the resistor is 1.0 Vrms
An elevator weighing 500 kg is to be lifted up at a constant velocity of 0.25 m/s. What would be the minimum horsepower of the motor to be used? G = 9.8 m/s2 and there is no frictional loss.
How many units of electric power will be consumed by 4 motors of 0.5 HP each in 8 hours?
Which of the following is not equivalent of Watts?
- ______ is defined as the time rate at which work is done or energy is transferred.
