Physics 3.4.1-2 Force, Energy, Momentum and Moments

16 flashcards · Physics · by TheoTyson

1. What is the difference between a scalar and vector quantity?

   A scalar has only a magnitude, whereas a vector has a magnitude and direction.

2. Are these quantities scalar or vector? mass, temperature, time, distance, speed, energy\text{mass, temperature, time, distance, speed, energy}mass, temperature, time, distance, speed, energy

   Scalar

3. Are these quantities scalar or vector? displacement, velocity, force, acceleration,\text{displacement, velocity, force, acceleration,}displacement, velocity, force, acceleration, momentum\text{momentum}momentum

   Vector

4. How can you add two vector quantities?

   Draw the vectors tip to tail and draw a line that connects the start and end point, or use trigonometry.

5. How do you work out the vertical component of a vector?

   vvertical=vsin⁡θv_{\text{vertical}} = v \sin{\theta}vvertical​=vsinθ

6. How do you work out the horizontal component of a vector?

   vhorizontal=vcos⁡θv_{\text{horizontal}} = v \cos{\theta}vhorizontal​=vcosθ

7. What forces are shown on a free body diagram?

   All of the forces that act on a body.

8. What does a body in equilibrium mean?

   The body is not accelerating, all of the forces will be balanced, can be at rest or a constant velocity.

9. What is the moment of a force equal to?

   The force multiplied by the perpendicular distance from the point to the line of action of the force.

10. What is the principal of moments?

    For a body to be in equilibrium, the sum of the clockwise moments must be equal to the sum of the anticlockwise moments.

11. What is a couple?

    A pair of coplanar forces with equal magnitudes that act parallel to each other but in opposite directions.

12. What is the moment of a couple equal to?

    The force multiplied by the perpendicular distance between the two lines of actions of the forces.

13. What is the centre of mass?

    The single point which it can be considered that all of the weight acts.

14. Where is the centre of mass of a uniform regular solid?

    The centre of the object.

15. What is inertia?

    The resistance to a change in velocity.

16. When will an object become unstable?

    When its centre of mass is not positioned over the base of an object.