You visited us 2 times! Enjoying our articles? Unlock Full Access!

Byju's Answer

Standard XII

Physics

Correlation to Linear Motion

A boat's prop...

Question

A boat's propeller has a rotational inertia of $4 {kg-m}^{2}$ . After a constant torque is applied for $12 s$ , the propeller's angular speed changes from a clockwise $8 rad/s$ to counter-clock wise $8 rad/s$ . What was the torque applied to the propeller?

4.3 N-m

No worries! We‘ve got your back. Try BYJU‘S free classes today!

5.3 N-m

Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses

6.3 N-m

No worries! We‘ve got your back. Try BYJU‘S free classes today!

7.3 N-m

No worries! We‘ve got your back. Try BYJU‘S free classes today!

Open in App

Solution

The correct option is B $5.3 N-m$
We know that, torque,

$τ = \frac{Δ L}{Δ t} = \frac{I (ω_{f} - ω_{i})}{Δ t}$

$\Rightarrow τ = \frac{4 [8 - (- 8)]}{12} = 5.3 N-m$

Hence, option $(B)$ is the correct answer.

Suggest Corrections

Similar questions

20 Nm

torque is applied to a flywheel that rotates about a fixed axis and has moment of inertia of

25 {kgm}^{2}

. If the flywheel is initially at rest, what is its angular velocity after it has turned through

10

revolutions?

Q. A solid sphere of diameter 25 cm and mass 25kg rotates about an axis through its centre. Calculate its moment of inertia, if its angular velocity changes from 2 rad/s to 12 rad/s in 5 second. Also calculate the torque applied.

Q. Angular velocity of a body of moment of inertia 100

k g {- m}^{2}

change from 2 rad/s to 4 rad/s in one minute. if constant torque acting on the body is 10 Nm, then the angle described by the body in one minute is:

Q. A wheel rotating at a speed of

600 rpm

(revolutions per minute) about its axis is brought to rest by applying a constant torque for

10

seconds. The angular velocity

5

seconds after the application of the torque is

n π rad/s

where

n

To maintain a rotor at a uniform angular speed of 200 rad s^–1, an engine needs to transmit a torque of 180 Nm. What is the power required by the engine?

(Note: uniform angular velocity in the absence of friction implies zero torque. In practice, applied torque is needed to counter frictional torque). Assume that the engine is 100 % efficient.

Join BYJU'S Learning Program

Explore more

Correlation to Linear Motion

Standard XII Physics

Join BYJU'S Learning Program

A boat's propeller has a rotational inertia of 4 kg-m2. After a constant torque is applied for 12 s, the propeller's angular speed changes from a clockwise 8 rad/s to counter-clock wise 8 rad/s. What was the torque applied to the propeller?

The correct option is B 5.3 N-mWe know that, torque, τ=ΔLΔt=I(ωf−ωi)Δt ⇒τ=4[8−(−8)]12=5.3 N-m Hence, option (B) is the correct answer.

A boat's propeller has a rotational inertia of $4 {kg-m}^{2}$ . After a constant torque is applied for $12 s$ , the propeller's angular speed changes from a clockwise $8 rad/s$ to counter-clock wise $8 rad/s$ . What was the torque applied to the propeller?

The correct option is B $5.3 N-m$
We know that, torque,

$τ = \frac{Δ L}{Δ t} = \frac{I (ω_{f} - ω_{i})}{Δ t}$

$\Rightarrow τ = \frac{4 [8 - (- 8)]}{12} = 5.3 N-m$

Hence, option $(B)$ is the correct answer.