The salesman is telling you the average magnitude of the car's acceleration.
| Acceleration | = (change in speed) / (time for the change)
| Acceleration | = (60 mi/hr) / (6 sec)
| Acceleration | = 10 miles/hr-sec
That would be 36,000 miles per hour squared,
or 0.0028 mile per second squared.
Speed = (distance) / (time)
Speed = (2.3 m) / (3 sec)
Speed = (2.3/3) (m/s)
<em>Speed = 0.766... m/s</em>
Are you asking about independent and dependent variables?
Answers:
a) -2.54 m/s
b) -2351.25 J
Explanation:
This problem can be solved by the <u>Conservation of Momentum principle</u>, which establishes that the initial momentum
must be equal to the final momentum
:
(1)
Where:
(2)
(3)
is the mass of the first football player
is the velocity of the first football player (to the south)
is the mass of the second football player
is the velocity of the second football player (to the north)
is the final velocity of both football players
With this in mind, let's begin with the answers:
a) Velocity of the players just after the tackle
Substituting (2) and (3) in (1):
(4)
Isolating
:
(5)
(6)
(7) The negative sign indicates the direction of the final velocity, to the south
b) Decrease in kinetic energy of the 110kg player
The change in Kinetic energy
is defined as:
(8)
Simplifying:
(9)
(10)
Finally:
(10) Where the minus sign indicates the player's kinetic energy has decreased due to the perfectly inelastic collision
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