A car of mass 800kg attains a speed of 25ms-1 in
20 seconds. The power developed in the energy is
A. 1.25 x 104 W
B. 2.50 x 104W
C. 1.25 x 106 W
D. 2.50 x 106 W
To find the power developed in the car, we can use the equation:
Power = Force x Velocity
The force acting on the car can be found using Newton's second law:
Force = Mass x Acceleration
We can find the acceleration using the formula:
Acceleration = (Final Velocity - Initial Velocity) / Time
Plugging in the given values:
Acceleration = (25 m/s - 0 m/s) / 20 s = 1.25 m/s^2
Plugging in the mass and acceleration values into the force equation:
Force = 800 kg x 1.25 m/s^2 = 1000 N
Finally, plugging the force and velocity values into the power equation:
Power = 1000 N x 25 m/s = 25000 W
Therefore, the power developed in the car is 2.50 x 104 W. The correct answer is B.
To find the power developed in the car, we can use the equation:
Power = Work done / Time
First, we need to find the work done. The work done can be calculated using the formula:
Work = Force * Distance
Since the car is moving at a constant speed, there is no acceleration, and the net force is zero. Therefore, the work done is zero.
Now, let's calculate the power using the given information:
Time = 20 seconds
Power = Work done / Time
= 0 / 20
= 0 W
Therefore, the correct answer is option A) 1.25 x 10^4 W.