- #1
magiclink
- 23
- 0
Hi! I'm extremely confused by this problem. A car of mass 1200 kg starts from rest and travels along a horizontal straight road. The engine of the car develops a constant power of 54 kW. All the energy produced by the engine goes into increasing the kinetic energy of the car.
The questions about this scenario go as follows (at time=5)
What is the instantaneous velocity?
I thought simply using Kinetic energy formula I could figure out the speed= 2.1m/s (roughly)
Now what confuses me is the next question. It asks to find the instantaneous acceleration at t=5. I figured that P=f*v would be a good choice. But other than that I'm at a loss. the formula doesn't quite make sense to me, although i know it's basically f*d/t. If power is constant however, would that mean the force acting on the car is also constant? And wouldn't this mean the acceleration is constant too? Then why does the instantaneous acceleration change at different velocities? Could someone explain the ins and outs of this formula? I cannot wrap my head around it.
P=F*v
(mv^2)/2
The questions about this scenario go as follows (at time=5)
What is the instantaneous velocity?
I thought simply using Kinetic energy formula I could figure out the speed= 2.1m/s (roughly)
Now what confuses me is the next question. It asks to find the instantaneous acceleration at t=5. I figured that P=f*v would be a good choice. But other than that I'm at a loss. the formula doesn't quite make sense to me, although i know it's basically f*d/t. If power is constant however, would that mean the force acting on the car is also constant? And wouldn't this mean the acceleration is constant too? Then why does the instantaneous acceleration change at different velocities? Could someone explain the ins and outs of this formula? I cannot wrap my head around it.
P=F*v
(mv^2)/2