Torque - AP Physics C: Mechanics
Card 1 of 30
Calculate torque: $F = 25,\text{N}$, $r = 2,\text{m}$, $\theta = 30^{\circ}$.
Calculate torque: $F = 25,\text{N}$, $r = 2,\text{m}$, $\theta = 30^{\circ}$.
Tap to reveal answer
$25,\text{N}\cdot\text{m}$. $\tau = 25 \times 2 \times \sin(30°) = 50 \times 0.5$
$25,\text{N}\cdot\text{m}$. $\tau = 25 \times 2 \times \sin(30°) = 50 \times 0.5$
← Didn't Know|Knew It →
What is the effect of increasing the lever arm on torque?
What is the effect of increasing the lever arm on torque?
Tap to reveal answer
Increases torque. Longer lever arm multiplies the rotational effect.
Increases torque. Longer lever arm multiplies the rotational effect.
← Didn't Know|Knew It →
Define torque in terms of rotational motion.
Define torque in terms of rotational motion.
Tap to reveal answer
Torque is the rotational equivalent of force. It causes rotational motion like force causes linear motion.
Torque is the rotational equivalent of force. It causes rotational motion like force causes linear motion.
← Didn't Know|Knew It →
What is the torque if the force is applied at the pivot?
What is the torque if the force is applied at the pivot?
Tap to reveal answer
Zero. Lever arm distance is zero at the pivot.
Zero. Lever arm distance is zero at the pivot.
← Didn't Know|Knew It →
What does a zero net torque imply about rotational motion?
What does a zero net torque imply about rotational motion?
Tap to reveal answer
No angular acceleration. From $\tau = I\alpha$, if $\tau = 0$ then $\alpha = 0$.
No angular acceleration. From $\tau = I\alpha$, if $\tau = 0$ then $\alpha = 0$.
← Didn't Know|Knew It →
State the condition for rotational equilibrium.
State the condition for rotational equilibrium.
Tap to reveal answer
Net torque is zero. Sum of all torques equals zero for no rotation.
Net torque is zero. Sum of all torques equals zero for no rotation.
← Didn't Know|Knew It →
How does torque change if force direction is parallel to lever arm?
How does torque change if force direction is parallel to lever arm?
Tap to reveal answer
Torque is zero. $\sin(0°) = 0$ makes torque zero.
Torque is zero. $\sin(0°) = 0$ makes torque zero.
← Didn't Know|Knew It →
Identify the pivot point in a torque problem.
Identify the pivot point in a torque problem.
Tap to reveal answer
The point about which the object rotates. The axis or fulcrum about which rotation occurs.
The point about which the object rotates. The axis or fulcrum about which rotation occurs.
← Didn't Know|Knew It →
What is the effect of force magnitude on torque?
What is the effect of force magnitude on torque?
Tap to reveal answer
Torque increases with force magnitude. Torque is directly proportional to force.
Torque increases with force magnitude. Torque is directly proportional to force.
← Didn't Know|Knew It →
Find the torque: $F = 10,\text{N}$, $r = 0.5,\text{m}$, $\theta = 90^{\circ}$.
Find the torque: $F = 10,\text{N}$, $r = 0.5,\text{m}$, $\theta = 90^{\circ}$.
Tap to reveal answer
$5,\text{N}\cdot\text{m}$. $\tau = 10 \times 0.5 \times 1 = 5$
$5,\text{N}\cdot\text{m}$. $\tau = 10 \times 0.5 \times 1 = 5$
← Didn't Know|Knew It →
Explain the effect of torque on a rolling object.
Explain the effect of torque on a rolling object.
Tap to reveal answer
Causes angular acceleration. Torque creates rotational motion in rolling objects.
Causes angular acceleration. Torque creates rotational motion in rolling objects.
← Didn't Know|Knew It →
What is the result of applying equal and opposite torques?
What is the result of applying equal and opposite torques?
Tap to reveal answer
No net torque. Equal magnitudes in opposite directions cancel out.
No net torque. Equal magnitudes in opposite directions cancel out.
← Didn't Know|Knew It →
State the principle of superposition for torque.
State the principle of superposition for torque.
Tap to reveal answer
Net torque is the sum of individual torques. Torques add vectorially like forces do.
Net torque is the sum of individual torques. Torques add vectorially like forces do.
← Didn't Know|Knew It →
What factor of torque is zero if force is applied at the pivot point?
What factor of torque is zero if force is applied at the pivot point?
Tap to reveal answer
Lever arm distance. Distance from pivot is the key factor.
Lever arm distance. Distance from pivot is the key factor.
← Didn't Know|Knew It →
What is the torque if the force is perpendicular to the lever arm?
What is the torque if the force is perpendicular to the lever arm?
Tap to reveal answer
$\tau = r \cdot F$. Simplified formula when $\sin(90°) = 1$.
$\tau = r \cdot F$. Simplified formula when $\sin(90°) = 1$.
← Didn't Know|Knew It →
Determine the net torque: $\tau_1 = 5,\text{N}\cdot\text{m}$, $\tau_2 = -3,\text{N}\cdot\text{m}$.
Determine the net torque: $\tau_1 = 5,\text{N}\cdot\text{m}$, $\tau_2 = -3,\text{N}\cdot\text{m}$.
Tap to reveal answer
$2,\text{N}\cdot\text{m}$. Add torques algebraically: $5 + (-3) = 2$
$2,\text{N}\cdot\text{m}$. Add torques algebraically: $5 + (-3) = 2$
← Didn't Know|Knew It →
Identify the units of torque in the SI system.
Identify the units of torque in the SI system.
Tap to reveal answer
Newton-meters (N·m). Force times distance has these units.
Newton-meters (N·m). Force times distance has these units.
← Didn't Know|Knew It →
Calculate torque: $F = 25,\text{N}$, $r = 2,\text{m}$, $\theta = 30^{\circ}$.
Calculate torque: $F = 25,\text{N}$, $r = 2,\text{m}$, $\theta = 30^{\circ}$.
Tap to reveal answer
$25,\text{N}\cdot\text{m}$. $\tau = 25 \times 2 \times \sin(30°) = 50 \times 0.5$
$25,\text{N}\cdot\text{m}$. $\tau = 25 \times 2 \times \sin(30°) = 50 \times 0.5$
← Didn't Know|Knew It →
What is the effect of a negative torque value?
What is the effect of a negative torque value?
Tap to reveal answer
Causes clockwise rotation. Negative indicates clockwise direction by convention.
Causes clockwise rotation. Negative indicates clockwise direction by convention.
← Didn't Know|Knew It →
Find torque: $F = 15,\text{N}$, $r = 4,\text{m}$, $\theta = 90^{\circ}$.
Find torque: $F = 15,\text{N}$, $r = 4,\text{m}$, $\theta = 90^{\circ}$.
Tap to reveal answer
$60,\text{N}\cdot\text{m}$. $\tau = 15 \times 4 \times 1 = 60$
$60,\text{N}\cdot\text{m}$. $\tau = 15 \times 4 \times 1 = 60$
← Didn't Know|Knew It →
Describe the effect of torque on an object's rotation.
Describe the effect of torque on an object's rotation.
Tap to reveal answer
Changes angular velocity. Torque produces angular acceleration per Newton's second law.
Changes angular velocity. Torque produces angular acceleration per Newton's second law.
← Didn't Know|Knew It →
State the relationship between torque and angular acceleration.
State the relationship between torque and angular acceleration.
Tap to reveal answer
$\tau = I\alpha$. Newton's second law for rotation.
$\tau = I\alpha$. Newton's second law for rotation.
← Didn't Know|Knew It →
What is the relationship between torque and rotational work?
What is the relationship between torque and rotational work?
Tap to reveal answer
$W = \tau \cdot \Delta \theta$. Work is torque times angular displacement.
$W = \tau \cdot \Delta \theta$. Work is torque times angular displacement.
← Didn't Know|Knew It →
What angle $\theta$ maximizes torque for a given force?
What angle $\theta$ maximizes torque for a given force?
Tap to reveal answer
$90^{\circ}$. $\sin(90°) = 1$ gives maximum value.
$90^{\circ}$. $\sin(90°) = 1$ gives maximum value.
← Didn't Know|Knew It →
Calculate torque for $r = 1,\text{m}$, $F = 10,\text{N}$, $\theta = 0^{\circ}$.
Calculate torque for $r = 1,\text{m}$, $F = 10,\text{N}$, $\theta = 0^{\circ}$.
Tap to reveal answer
Zero torque. $\sin(0°) = 0$ eliminates rotational effect.
Zero torque. $\sin(0°) = 0$ eliminates rotational effect.
← Didn't Know|Knew It →
How does an increase in moment of inertia affect angular acceleration?
How does an increase in moment of inertia affect angular acceleration?
Tap to reveal answer
Decreases angular acceleration. From $\tau = I\alpha$, larger $I$ gives smaller $\alpha$.
Decreases angular acceleration. From $\tau = I\alpha$, larger $I$ gives smaller $\alpha$.
← Didn't Know|Knew It →
Find torque: $F = 20,\text{N}$, $r = 3,\text{m}$, $\theta = 45^{\circ}$.
Find torque: $F = 20,\text{N}$, $r = 3,\text{m}$, $\theta = 45^{\circ}$.
Tap to reveal answer
$30\sqrt{2},\text{N}\cdot\text{m}$. $\tau = 20 \times 3 \times \sin(45°) = 60 \times \frac{\sqrt{2}}{2}$
$30\sqrt{2},\text{N}\cdot\text{m}$. $\tau = 20 \times 3 \times \sin(45°) = 60 \times \frac{\sqrt{2}}{2}$
← Didn't Know|Knew It →
What role does $\theta$ play in calculating torque?
What role does $\theta$ play in calculating torque?
Tap to reveal answer
Determines effectiveness of force. Angle controls the component of force causing rotation.
Determines effectiveness of force. Angle controls the component of force causing rotation.
← Didn't Know|Knew It →
Define the lever arm in a torque context.
Define the lever arm in a torque context.
Tap to reveal answer
Perpendicular distance from pivot to line of action. The effective distance that matters for rotation.
Perpendicular distance from pivot to line of action. The effective distance that matters for rotation.
← Didn't Know|Knew It →
What happens to torque if the distance from pivot doubles?
What happens to torque if the distance from pivot doubles?
Tap to reveal answer
Torque doubles. Torque is directly proportional to lever arm.
Torque doubles. Torque is directly proportional to lever arm.
← Didn't Know|Knew It →