The net force on the boy is zero.
Based on this analysis, I would expect the boy to <u>not accelerate</u>.
Answer:
When acceleration is zero (that is, a = dv/dt = 0), rate of change of velocity is zero. That is, acceleration is zero when the velocity of the object is constant. so probably D
Explanation:
D
Answer:
• As heat is applied to one end of this material, atoms in the hotter region gain vibràtory energy at a maximum amplitude. They transfer it on to their neighboring atoms and heat is transfered along this material in form of vibràtory energy.
Explanation:

Answer:
Speed Unchanged.
Explanation:
As work is defined as a product of force over a distance. If the distance in altitude is constant = 500km, there's 0 change in distance and force, no work would be done by the gravitational force.
Since potential energy of the satellite is unchanged, unless there's additional internal energy source, the kinetic energy would remain unchanged, so would its speed.
Their Period number is common means their "Principal Quantum Numbers" are same
Hope this helps!