Answer:
1.25 m/s
Explanation:
Given,
Mass of first ball=0.3 kg
Its speed before collision=2.5 m/s
Its speed after collision=2 m/s
Mass of second ball=0.6 kg
Momentum of 1st ball=mass of the ball*velocity
=0.3kg*2.5m/s
=0.75 kg m/s
Momentum of 2nd ball=mass of the ball*velocity
=0.6 kg*velocity of 2nd ball
Since the first ball undergoes head on collision with the second ball,
momentum of first ball=momentum of second ball
0.75 kg m/s=0.6 kg*velocity of 2nd ball
Velocity of 2nd ball=0.75 kg m/s ÷ 0.6 kg
=1.25 m/s
Answer:
3.75 hours
Explanation:
By 
where v is the velocity (or speed in this case)
d is the distance travelled
t is the time taken

Therefore it takes 3.75 hours for the bus to travel 150 km and 40 km/hr.
Answer:
3rd order polynomial
Explanation:
Given that the increase in the order of the polynomial the error between the curve fit and measured data will decreases hence :
The polynomial order that is best to use is the 3rd order polynomial, this is because using a 3rd order polynomial will produce a less variance and a low Bias
Is there any other information given? I don't think you can solve this without a time