Answer:
This question assumes that the car accelerates at the same rate as when it went from 0 to 60km/h
24.29m/s or 87.4km/h
Explanation:
Let's find the acceleration of the car:
let vi=0, vf=60km/h (16.67m/s), Δt = 8.0s
a = (vf-vi)/Δt
a = (16.67m/s-0)/8.0
a = 2.08m/s^2
Now we can use this acceleration to find vf in the second part:
50km/h is 13.89m/s
a = (vf-vi)Δt
vf = aΔt + vi
vf = 2.08m/s^2*5.0+13.89m/s
vf = 24.29m/s (87.4km/h)
Answer:
The kinetic energy of the phone would increase. The gravitational potential energy of the phone would decrease.
Explanation:
The kinetic energy 
of an object is proportional to the square of the speed of that object. If air resistance is negligible, the phone would accelerate under gravitational pull and speed up. Hence, the kinetic energy of the phone would increase.
The gravitational field near the surface of the earth is approximately constant. Hence, the gravitational potential energy 
of the phone would be proportional to its height. As the phone approaches the ground, the height of the phone becomes lower and the gravitational potential energy of the phone would decrease.
Answer:
10s
Explanation:
If it took Beatrice 25 seconds to complete the race
Distance = 100 meter
Beatrice speed = 100/25
= 4m/s
If Alice runs at a constant speed and crosses the finish line $5$ seconds, she must have completed the race in 20s (25 -5).
Her speed where constant
= 100/20
= 5 m/s
It would take Alice
= 50/5
= 10s
It would take Alice 10s to run $50$ meters.
Answer: 58.8235 km/h
speed = distance/time
the distance is 10 km
the time is 10 minutes
the unit is not correct, so we first change minute to hour
so 10/60 is 0.166667, rounded to 0.17.
10 km/ 0.17 hours =
