Physics · Work, Power & Energy
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A cyclist comes to a kidding stop in 10 m. During this process, the opposite force on the cycle due to road is 200N. How much work does the road do on cycle?
- A
(-1800 J)
- B
(-2000 J)
- C
2000 J
- D
1900 J
Skidding displacement, d=10m.
Force exerted on the cycle by the road, f=200N. Angle between the force exerted by the road on the cycle and the displacement of the cycle, θ=180°
Work done by the road on the cycle, w=?
Step 2: Formula used
w=fdcosθ ………………………(a)
Step 3: Calculation of the work done by the road on the cycle
Substituting the given values in equation (a), we get
w=200N×10m×cos1800
w=-2000J.
The negative sign indicates that the force and the displacement are opposite to each other.Hence, the magnitude of the work done by the road on the cycle is equal to 2000J.
This option is incorrect. The negative sign indicates that the work done by the road is in the opposite direction of the displacement. However, the value of -1800 J is not the correct work done.
The negative sign indicates that the work done by the road on the cycle is in the opposite direction of the displacement (which is stopping the cycle). This is the correct representation of the situation, and the work done is 2000 Joules. The negative sign indicates that the work done by the road is in the opposite direction of the displacement, which is the case when the cyclist stops.
This option is incorrect. It incorrectly assumes that the work done by the road is positive, meaning the road is helping the cyclist. However, in reality, the work done by the road is negative, as it acts in the opposite direction of the displacement.
This option is incorrect. The value of 1900 J is not the correct work done by the road on cyclist. The correct value is -2000 J, as explained earlier.
Tagged under Physics · Work, Power & Energy · 2022