A car starts from rest at a stop sign. It accelerates at 4.0 m/s^2 for 3 seconds, coasts for 2 s, and then slows down at a rate
2 answers:
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Answer:
13 m/s east
Explanation:
We can solve the problem by using the law of conservation of momentum, which states that the total momentum before the collision is equal to the total momentum after the collision:
where
m = 0.1 kg is the mass of each puck
u1 = +13 m/s is the initial velocity of puck 1
u2 = -18 m/s is the initial velocity of puck 2 (here I assume the west direction to be the negative direction, so I put a negative sign)
v1 = -18 m/s is the final velocity of puck 1
v2 = ? is the final velocity of puck 2
Simplifying m from the formula and substituting the data, we can find the final velocity of puck 2, v2:
And the positive sign means that puck 2 is moving east.
First, let's convert the initial angular speed from rpm (rev/min) into rad/s, keeping in mind that 
and 1 min=60 s:
Now we can find the angular acceleration of the lp, keeping in mind that the final speed is zero:
and the acceleration is negative because the LP is decelerating.
Now we can find the angle covered by the LP from the beginning to the end of its motion:
And finally, we can convert it into number of revolutions:
Now we can find the angular acceleration of the lp, keeping in mind that the final speed is zero:
and the acceleration is negative because the LP is decelerating.
Now we can find the angle covered by the LP from the beginning to the end of its motion:
And finally, we can convert it into number of revolutions: