Answer:
i think it is iron
Explanation:
its the only one that makes sense to me
Radio waves are the longest
B.Electromagnetic
explanation:
Explanation:
It is given that,
The Displacement x of particle moving in one dimension under the action of constant force is related to the time by equation as:

Where,
x is in meters and t is in sec
We know that,
Velocity,

(a) i. t = 2 s

At t = 4 s

(b) Acceleration,

Pu t = 3 s in above equation
So,

Hence, (a) (i) v = 55 m/s (ii) v = 211 m/s and (b) 78 m/s²
So the force that the gymnast with a mass m=45 kg, has to exert against the ground to stop if her acceleration is a=8*g, where g=9.81 m/s², can be obtained from the Newtons second law: F=m*a, where F is the force, m is the mass and a is acceleration.
F=m*a=m*8*g=45*8*9.81=3531.6 N.
So the force that a gymnast has to exert on the mat in order to stop is F=3531.6 N.