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My answers
Answer:
2.5 kg.m/s
Explanation:
Taking left side as positive while right side direction as negative then
Momentum, p= mv where m is the mass of the object and v is the velocity of travel
Momentum for ball moving towards right side=mv=2.5*-3=-7.5 kg.m/s
Momentum for the ball moving towards the left side=mv=2.5*4=10 kg.m/s
Total momentum=-7.5 kg.m/s+10 kg.m/s=2.5 kg.m/s
The answer is 24 J
F K =.25*8 N
= 2N
F = f k = 2 N
Since a = 0
W = f * s
2 N * 12 m = 24 J
The coefficient of friction is a ratio used to quantify the friction force among two gadgets when it comes to the everyday pressure this is keeping them collectively. The coefficient of friction is critical attention at some stage in material selection and floor requirement determination.
For instance, ice on steel has a low coefficient of friction – the 2 materials slide past each different without problems – whilst rubber on the pavement has an excessive coefficient of friction – the substances no longer slide past each other without difficulty.
The coefficient of friction is dimensionless and it does not have any unit. it is a scalar, meaning the direction of the force does not have an effect on the physical quantity. The coefficient of friction depends on the gadgets that are causing friction.
Learn more about the coefficient of friction here brainly.com/question/20241845
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Answer:

Explanation:
First we have to find the time required for train to travel 60 meters and impact the car, this is an uniform linear motion:

The reaction time of the driver before starting to accelerate was 0.50 seconds. So, remaining time for driver is 1.5 seconds.
Now, we have to calculate the distance traveled for the driver in this 0.5 seconds before he start to accelerate. Again, is an uniform linear motion:

The driver cover 10 meters in this 0.5 seconds. So, the remaining distance to be cover in 1.5 seconds by the driver are 35 meters. We calculate the minimum acceleration required by the car in order to cross the tracks before the train arrive, Since this is an uniformly accelerated motion, we use the following equation:

By the work energy theorem, the total work done on the stone is given by its change in kinetic energy,

We have


Then the total work is
