The answer for this question is acceleration
Answer:
-1.09m/sec^2
Explanation:
Acceleration= (Vf-Vi)/Time
=12-54.8
= -42.8
= -42.8/39
=-1.09
-ve sign is due to recoil of train
as it suddenly hits brakes.
Answer:
the number of additional car lengths approximately it takes the sleepy driver to stop compared to the alert driver is 15
Explanation:
Given that;
speed of car V = 120 km/h = 33.3333 m/s
Reaction time of an alert driver = 0.8 sec
Reaction time of an alert driver = 3 sec
extra time taken by sleepy driver over an alert driver = 3 - 0.8 = 2.2 sec
now, extra distance that car will travel in case of sleepy driver will be'
S_d = V × 2.2 sec
S_d = 33.3333 m/s × 2.2 sec
S_d = 73.3333 m
hence, number of car of additional car length n will be;
n = S_n / car length
n = 73.3333 m / 5m
n = 14.666 ≈ 15
Therefore, the number of additional car lengths approximately it takes the sleepy driver to stop compared to the alert driver is 15
Answer:
Newtows first law of motion
The acceleration of gravity is inversely proportional to
the square of the distance from Earth's center.
The acceleration of gravity is 9.8 m/s² on the Earth's surface ...
6380 km from the center.
If the acceleration of gravity at 'h' is 4.9 m/s² ... 1/2 of what it is
on the surface, then the distance from the center is
(6380 x √2) = 9,023 km (rounded) ,
and 'h' is the distance above the surface
= (9,023 - 6,380) = 2,643 km (rounded) .
