Answer:
i don't know how to explain it but I think it's just the way you do it by yourself
Given that,
For glasses:
distance, s = 42 m
a= -g = -9.81 m/s²
we can calculate time taken by glasses to hit the ground as follow:
s= Vi* t + 1/2 at²
Since at top initial velocity, Vi= 0
42 = 0 - 0.5* 9.81 t²
t = 2.926 s
Pen is drop 2 second after the glasses is dropped. So time difference will be:
Δt = 2.926 - 2 = 0.926 s
Distance covered by Pen in 0.926 s can be calculated as:
s = 0 - 0.5* 9.81 * 0.926²
s= 4.2 m
Distance of pen from ground will be, 42-4.2 = 37.8 m
When the glasses hit the ground, the pen will be 37.8 m above the ground.
Answer: Speed = 4m/s
Strength = 7.1T
Explanation: P= 4.0w
N = 1.0
V= ?
Power = force x velocity
Velocity = power/ force
V= 4.0w/1.0N
V = 4m/s
Strength of the magnetic field
B = √PR / lv
Where; l = length 10cm
R= 2.0
P= 4.0w
V= 4m/s
B = √ (4.0w) × (2.0) / (10cm) × (4m/s)
B = 7.1T
