[PHYSICS]

• Physics


  Science that investigates the fundamental concepts of matter, energy, space, and the relationships among them
• Quantities in physics


  • Scalar (has magnitude)
  • Vector (has magnitude and direction)
• Scalar quantities


  • Distance
  • Speed
  • Mass
  • Temperature
• Vector quantities


  • Displacement
  • Velocity
  • Force
  • Acceleration
  • Time
• Scalar quantity


  • Ant moved 5cm right, 3cm left, then 6cm right again
  • Distance = 5 + 3 + 6 = 14cm
  • Displacement = 5 - 3 + 6 = 8cm
• Distance


  Distance between all points regardless of direction
• Displacement


  • Change of position of an object from its original place
  • Going left is negative, going right is positive
• Speed


  How fast an object is moving (distance/time)
• Velocity


  • Rate of change of an object's position (displacement/time)
  • Has both magnitude and direction
• Uniform motion


  • Movement of an object along a straight line at a constant speed
• Non-uniform motion


  • Object covering a total distance at different speeds/velocities
• Acceleration


  • Change of velocity in an object over time
  • Can be change in speed or change in direction
• Uniformly accelerated motion


  • Object is speeding up, slowing down, or changing direction at a constant rate
• Cara runs 2 km south and 3 kmnorth. What is her total distanceand displacement?

  Answers:

  Total distance : 5 km

  Displacement : 1km, North
• Leah walked 7 km east, then 10 km west, and back again 12 km east. What is her distance and displacement?

  Answers:

  Total distance : 29 km

  Displacement : 9 km, East
• A person walked 6m to the right, and 4m left. The

  time of walking was recorded to be 4.4s.

  What was the speed of the person?

  Answer: 2.27 m/s
• A Ford Model T car travelled 45 kilometers

  East within 3 hours. What is its velocity?

  
  

  Answer =15 km/hr East
• A female cyclist traveled 20 km north and 15 km south in 7 hours. What was her speed? her velocity?

  Answer: 0.71 km/hr, North
• The cheetah, the fastest of land animals, can run a distance of 274 m in 8.65 seconds. What is the cheetah’s speed?

  Answer: 31.68 m/s
• A high school bus travels 240 km in 6.0 h. What is its

  average speed for the trip?

  Answer: 40.00 km/hr
• A spider travels across a driveway 3.6 m wide with a

  speed of 0.15 m/s. How long will it take to cross the

  driveway?

  Answer: 24.00s
• A motorist traveling on a straight stretch of open highway sets his cruise control at 90.0 km/h. How far in km will he travel in 15 minutes?

  Answer: 22.50 km
• Uniform motion describes the movement of

  an object along a straight line at a constant

  speed.
• If the average velocity of the person is +2m/s,

  what is the displacement covered after 6.5s ?

  Ans: 13.00 m
• If the object in motion covers at total distance at different speeds or velocities, then the object is said to bein non-uniform motion.
• What do you call the change of velocity in objects over time?

  Acceleration ( a with arrow above )
• Acceleration ( a ): is the change in velocity with respect to time. It measures how fast an object changes its velocity.
• Acceleration can be one of the following:

  • change in direction
  • change in speed/velocity
• a : acceleration (m/s2

  Vf : final velocity (m/s)

  Vi : initial velocity (m/s)

  t : time (s)
• a = Vf – Vi/t
• Lightning McQueen was speeding constantly at

  +14m/s, and within 4 seconds, sped up to +20m/s to

  get ahead of another car.

  a = 1.50 m/s2
• A yellow cab passed in a pedestrian crossing and

  was slowed down by a speed bump. From +13m/s,

  the car’s speed lowered to +4m/s within 3 seconds.

  a = - 3.00 m/s2
• speeding up (accelerate) = positive

  speeding down (decelerate) = negative
• A sports bike can accelerate from rest to a speed of 28

  m/s East to the right in 20 s. What is its acceleration?

  Ans: a = 1.40 m/s^2 East
• A bus moving at +20 m/s East slows at a rate of -4 m/s^2

  and stopped. How long does it take the bus to stop?

  Ans: t = 5.00 s
• The speed of sound while in air is 343 m/s to the right. When sound waves travel from air to water, it accelerates at 813.08 m/s^2 to the right within 1.3 seconds. What is the final velocity of the sound waves when they travel on water?

  Ans: vf = 1400.00 m/s
• A roller coaster car starts down the slope with its velocity at 4 m/s South. But 3 seconds later, at the bottom of the slope, its velocity is 22 m/s South. What’s its acceleration?

  Ans: 6.00 m/s^2 South
• How much time does it take for Usain Bolt to go from zero to 12m/s to the right if his acceleration is 9.5 m/s^2 to the right?

  Ans: 1.26 s