Answer:
-6.6 km/h
Explanation:
In 7hr plane travelled 2020km;
For the first 4hr the average speed was 310km/h;
d=st, s=d/t;
Distance covered in first 4h is d = 310km/h×4h = 1240km;
See the image attached for further solution
Distance ( say d ) is directly proportional to time ( say t ) .
mathematically ,
d = kt
where k is constant if proportionality .
Now differentiating the above equation with respect to time ,
we get ;
v = k
=> velocity is constant .
=> No acceleration .
the answer to your question is 10.5 kJ
Answer:
The speed of the vehicles immediately after the collision is 5.84 m/s.
Explanation:
The speed of the vehicles after the collision can be found by conservation of linear momentum:


Where:
m₁: is the mass of the car = 0.5 ton = 500 kg
m₂: is the mass of the lorry = 9.5 ton = 9500 kg
: is the initial speed of the car = 40 km/h = 11.11 m/s
: is the initial speed of the lorry = 20 km/h = 5.56 m/s
: is the final speed of the car =?
: is the final speed of the lorry =?
Since the two vehicles become tightly locked together after the collision
=
:


Therefore, the speed of the vehicles immediately after the collision is 5.84 m/s.
I hope it helps you!
The answer is true. A person can only see object placed at 40 cm from him.
Hope I helped. ^-^
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