Question

A 5g coin is dropped into a hollow cylinder carrying a current of 10 A, the coin will
a. accelerate
b. decelerate
(the coin decelerate whyy??)​

Answer 1

Answer:

Given,

Mass of the ball = 0.5 kg

Initial speed, u = 5 m/s towards west

Force acting on the ball = -10 N

Thus, acceleration produced = F/m = -10/0.5

a = -20 ms-2

( 1 ) At t = -10s

Acceleration, a’ = 0, u = 5 m/s

s = ut + ½ at2

= 5(-10) + 0

= -50m

( 2 ) At t = 20

Acceleration, a’’ = -20 m/s2 and u =5 m/s

S = ut + ½ a’’t2

S = 5×20 + ½ (-20)(202)

S = 100 – 4000 = -3900m

( 3 ) At t = 100 s

For 0\leq t\leq 30 s0≤t≤30s

a = -20 m/s2

u = 5 m/s

s1 = ut + ½ at2

= 5 x 30 + ½ (-20)(30)2

= 150 – 9000 = -8850 m

For 30\leq t\leq 100 s30≤t≤100s

Using the first equation of motion, for t = 30 s,

v = u + at (Where v is the final velocity)

= 5 + (–20) × 30 = –595 ms-1

Velocity of the body after 30 s = –595 ms-1

For motion between 30 s to 100 s (i.e. 70 s) :

s2 = vt + ½ a’’t2

= -595(70) + ½ (0)t2 = -41650m

Therefore, the total distance, S = s1 + s2 = -8850 – 41650 = -50500m