Question

A lift of mass 1000 kg is moving upwards with an acceleration of 1 m/s2. The tension developed in the
string, which is connected to lift is : (g = 9.8 m/s2)
(1) 9800 N
(2) 10800 N
(3) 11000 N
(4) 10000 N​

Answer 1

Given:

Mass of lift (m) = 1000 kg

Acceleration of lift (a) = 1 m/s²

Acceleration due to gravity (g) = 9.8 m/s²

To Find:

Tension developed in the string (T)

Answer:

For a lift which is moving in upward direction with an acceleration (a), the tension (T) developed in the string connected to the lift is given by:

$\bf \leadsto T = m(g + a) \\ \\ \rm \leadsto T = 1000(9.8 + 1) \\ \\ \rm \leadsto T = 1000 \times 10.8 \\ \\ \rm \leadsto T = 10800 \ N$

$\therefore$ Tension developed in the string (T) = 10800 N

Correct Option: $\boxed{\mathfrak{(2) \ 10800 \ N}}$

Answer 2

T - mg = ma

T = mg + ma

T = m(g + a)

= 1000(9.8 + 1)

= 10800 N