physics- mechanics & energy

Question 1

Right Hand Rule:

Answer 1

1. Start by pointing your thumb in the direction of vector A.
2. Extend your fingers in the direction of vector B. You may need to rotate your wrist to get the correct configuration of thumb and fingers.
3. Your palm establishes the plane between the two vectors. The direction your palm points is the direction of the resultant C

Question 2

1 Kilogram of material on earth will have _________________ on the moon:

Answer 2

• will have the same mass as 1 kilogram on the moon

Question 3

Newton’s 3 laws:

Answer 3

1. in the absence of any forces -or when the total force is zero-there will be no change in velocity
2. acceleration results from the sum of the force vectors
3. for any two interacting objects, all forces acting on one object have an equal acting on the other object

Question 4

Concept Check 1.6

How do the forces acting in free fall & projectle motion differ?

Answer 4

• the only force acting in both free fall & projectile motion is GRAVITY

Question 5

Concept Check 1.6

At what angle of launch is a projectile going to have the greatest horizontal displacement? What angle will result in the greatest vertical displacement, assuming a level surface?

Answer 5

• The product of sine and cosine is maximized when the angle is 45°.
• Because horizontal displacement relies on both measurements, the maximum horizontal displacement will also be achieved at this angle, 45.
• Vertical displacement will always be zero as the object returns to the starting point. Objects launched vertically will experience the greatest vertical distance.

Question 6

CC: 1.6

What is the equation for centripetal acceleration

Answer 6

• the equation for centripetal force is F_c=mv²/r, and force is simply mass times acceleration (from Newton’s second law), then a_c= v²/r

Question 7

1.7 CC

Can a moving object be in equilibrium? Why or why not?

Answer 7

• a moving object can be in either translational or rotational equilibrium (or both)
• Translational equilibrium only requires the net force on an object be zero-it’s velocity is constant
• Rotational equilibrium is that net torque equals zero-its angular velocity is constant

Question 8

1.7 CC

If you have an object 3 times as heavy as you can lift, how could a lever be used to lift the object, where would the fulcrum need to be placed?

Answer 8

• One could place the fulcrum one quarter of the way across the lever, closer to the object.
  
  • The ratio of the lever arms would then be 3:1, which means that only one-third of the original force is necessary.
• (Alternatively, the fulcrum could be placed at the end with the object one-third of the way across the lever. This would again result in a 3:1 ratio of lever arms, meaning that only one-third of the original force is necessary.)

Question 9

Conservative Forces

Answer 9

Question 10

WORK

Answer 10

Question 11

Waves

Answer 11