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:
Answer:
Second Trial satisfy principle of conservation of momentum
Explanation:
Given mass of ball A and ball B 
Let mass of ball 
and 
Final velocity of ball 
Final velocity of ball 
initial velocity of ball 
Initial velocity of ball 
Momentum after collision 
Momentum before collision 
Conservation of momentum in a closed system states that, moment before collision should be equal to moment after collision.
Now, 
Plugging each trial in this equation we get,
First Trial
momentum before collision 
moment after collision
Second Trial
moment before collision 
moment after collision
Third Trial
momentum before collision moment after collision
Fourth Trial
momentum before collision moment after collision
We can see only Trial- 2 shows the conservation of momentum in a closed system.
Answer:
6m/s
Explanation:
the original momentum = mass x velocity = 8x (60+10) = 560
momentum after = mass x velocity of the school bag + mass x velocity of the boy = 10x20 + 60x A
200+60A = 560
A=6
