Answer:
Point number 3.
Explanation:
Volcanism can be studied to found out evidence of the internal structure of the Earth.
Answer:
Speed of the speeder will be 28 m/sec
Explanation:
In first case police car is traveling with a speed of 90 km/hr
We can change 90 km/hr in m/sec
So 
Car is traveling for 1 sec with a constant speed so distance traveled in 1 sec = 25×1 = 25 m
After that car is accelerating with
for 7 sec
So distance traveled by car in these 7 sec

So total distance traveled by police car = 224 m
This distance is also same for speeder
Now let speeder is moving with constant velocity v
so 
v = 28 m/sec
Unlike a longitudinal wave, a transverse wave moves about, perpendicular to the direction of propagation. The particles in a transverse wave do not travel along the direction of propagation, but only oscillate up and down on its equilibrium position. With this, the displacement can be determined by measuring (in the case of electronic waves, using an oscilloscope or spectrum analyzer) and setting the desired units to measure the wave in.
Fortunately, 'force' is a vector. So if you know the strength and direction
of each force, you can easily addum up and find the 'resultant' (net) force.
When we talk in vectors, one newton forward is the negative of
one newton backward. Hold that thought, while I slog through
the complete solution of the problem.
(100 N forward) plus (50 N backward)
= (100 N forward) minus (50 N forward)
= 50 N forward .
That's it.
Is there any part of the solution that's not clear ?