Exam 3 Flashcards
(15 cards)
Is it possible for a system to have negative potential energy
Yes since the choice of zero potential energy is arbitrary
You slam on the brakes of your car in a panic and scared a certain distance on the street level Road if you had been traveling twice as fast what distance With the car have skidded under the same conditions
It would have skidded 4 times farther
If you push twice as hard against a stationary brick wall the amount of work you do
Remains constant at zero. No work done
The total mechanical energy of a system
Is constant only if conservative forces act
To accelerate your car at a constant acceleration the cars engine must
Maintain a constant power output
If the net work done on an object is zero then the objects kinetic energy
Remains the same
Consider a plot of the displacement x vs applied force F for an ideal elastic spring. The slope would be
The reciprocal of the spring constant
The work energy theorem says
The net work done plus the initial kinetic energy is the final kinetic energy
Tight rope walker’s walk with a long flexible rod in order to
Lower the center of mass
Some automobiles have airbags installed on the dashboard as a safety measure the impact of a collision causes the airbag to inflate and it then cushions a passengers head when he has thrown forward into the car suppose that such an airbag could lengthen the collision time between one’s head on the dashboard by a factor of 10 what effect will this have on the force exerted on the head
The force would be reduced by a factor of 10
Consider to unequal masses capital M and m Which of the following statements is false
If a uniform rod of mass m were to join the two masses this would not alter the position of the center of mass of the system without the rod present
In a game of pool the white cue ball hits the number five ball and stops on the number five ball moves away with the same velocity as the cue ball had originally the type of collision is
Elastic
A golf ball traveling 3 m/s to the right collide in a head-on collision with a stationary bowling ball in a fraction free environment at the collision is almost perfectly elastic the speed of the golf ball immediately after the collision is
Slightly less than 3m/s
A proton of mass m and speed v Strike an alpha particle which consist of two Protons and two neutrons at rest at the collision is completely elastic what speed while the alpha particle have after the collision
2/5v
When you lift a beverage can from the table to the mouth you do how much work
1 joule
