Atennis player tosses a tennis ball straight up and then catches it after 2.00 s at the same height as the point of release. (a) what is the acceleration of the ball while it is in flight? (b) what is the velocity of the ball when it reaches its maximum height? find (c) the initial velocity of the ball and (d) the maximum height it reaches.

a) - 9.8 m/s²

b) 0 m/s

c) 9.8 m/s

d) 4.9 m

Explanation:

(a)

While the ball is in flight, acceleration due to gravity acts on it. hence

a = acceleration due to gravity = - 9.8 m/s²

The negative sign indicates downward direction

b)

At the maximum height, the ball comes to a momentary stop. hence the velocity of the ball at the maximum height is zero.

0 m/s

c)

Consider the motion of the ball

v₀ = initial velocity of the ball at the time of throw = v

a = acceleration due to gravity = - 9.8 m/s²

t = time interval = 2 s

v = final velocity just before he catch the ball = - v

using the kinematics equation

v = v₀ + a t

- v = v + (- 9.8) (2)

v = 9.8 m/s

d)

h = maximum height reached

v₀ = initial velocity of the ball at the time of throw = 9.8 m/s

v = final velocity of the ball at the highest point = 0 m/s

a = acceleration due to gravity = - 9.8 m/s²

using the equation

v² = v₀² + 2 a h

0² = 9.8² + 2 (- 9.8) h

h = 4.9 m

electromagnetic shielding is the practice of reducing the electromagnetic field in a space by blocking the field with barriers made of conductive or magnetic materials. shielding is typically applied to enclosures to isolate electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs. electromagnetic shielding that blocks radio frequency electromagnetic radiation is also known as rf shielding.

the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia

the maxium height is 34m/s