The last one is correct (D)
Answer:he formula for average speed is (total distance/total time)
the y-component does not matter in this problem. so do 6.26(cos45)=4.43m/s to find the x-component velocity which is constant throughout the duration of the flight. the total distance is 2L because he travels distance L twice.
the total time is ((time in water)+(time out of water)) since you dont have time you must eliminate it. to do this you need (distance)/(time)=velocity
solve for time and you get T=D/V
time in water is L/3.52 and time out of water is L/4.43
add them together and you get (4.43L+3.52L)/(15.59) = 7.95L/15.59
that value is your total time
divide you total distance (2L) by total time (7.95L/15.59) and the Ls cancel out and you get
(31.18)/(7.95) = 3.92 m/s = Average Speed
Explanation:
It is 72 km/h
I hope it helps
Answer:
He needs 1.53 seconds to stop the car.
Explanation:
Let the mass of the car is 1500 kg
Speed of the car, v = 20.5 m/s
He will not push the car with a force greater than, 
The impulse delivered to the object is given by the change in momentum as :

So, he needs 1.53 seconds to stop the car. Hence, this is the required solution.