The distance covered by car is equal to (assuming it is moving by uniform motion) the product between the car's speed and the time of the car ride, 4 h:

where

is the car's speed

is the duration of the car ride
Similarly, the distance covered by train is equal to the product between the train's speed and the duration of the train ride, 7 h:

The total distance covered is S=255 km, which is the sum of the distances covered by car and train:

which becomes

(1)
we also know that the train speed is 5 km/h greater than the car's speed:

(2)
If we put (2) into (1), we find

and if we solve it, we find


So, the car speed is 20 km/h and the train speed is 25 km/h.
The kinetic energy of the child at the bottom of the incline is 106.62 J.
The given parameters:
- <em>Mass of the child, m = 16 kg</em>
- <em>Length of the incline, L = 2 m</em>
- <em>Angle of inclination, θ = 20⁰</em>
The vertical height of fall of the child from the top of the incline is calculated as;

The gravitational potential energy of the child at the top of the incline is calculated as;

Thus, based on the principle of conservation of mechanical energy, the kinetic energy of the child at the bottom of the incline is 106.62 J since no energy is lost to friction.
Learn more about conservation of mechanical energy here: brainly.com/question/332163
Answer:
133.8 N
Explanation:
Recall that the acceleration of gravity in Neptune is estimated as 11.15 m/s^2
Therefore, the weight of the dog on this planet would be:
Weight = mass x acceleration of gravity = 12 kg x 11.15 m/s^2 = 133.8 N
Answer:
B
Explanation:
V=IR I= curren V=volt R=resistor
8=2.R 8/2=R R=4