Formula of relative displacement
1 answer:
You might be interested in
This type of a problem can be solved by considering energy transformations. Initially, the spring is compressed, thus having stored something called an elastic potential energy. This energy is proportional to the square of the spring displacement d from its normal (neutral position) and the spring constant k:
So, this spring is storing almost 12 Joules of potential energy. This energy is ready to be transformed into the kinetic energy when the masses are released. There are two 0.2kg masses that will be moving away from each other, their total kinetic energy after the release equaling the elastic energy prior to the release (no losses, since there is no friction to be reckoned with).
The kinetic energy of a mass m moving with a velocity v is given by:
And we know that the energies are conserved, so the two kinetic energies will equal the elastic potential one:
From this we can determine the speed of the mass:
The speed will be 7.74m/s in in one direction (+), and same magnitude in the opposite direction (-).
Answer 1) : 62.5 km/hour is the average velocity of the train.
2) The final velocity of the car at the end of 75 m is 14.69 m/s
Explanation:
1) Displacement of the train = 100 km + 150 km = 250 km
Total time train took =1 hour 15 min+ 45 min + 2 hours = 240 min = 4 hours
Average velocity=
62.5 km/hour is the average velocity of the train.
2) The acceleration of the car, a= 1.2
Distance covered by the car,s = 75 m
Initial velocity of the car , = 6 m/s
Final velocity of thre car ,=?
Using third equation of motion:
The final velocity of the car at the end of 75 m is 14.69 m/s