Anonymous
Anonymous asked in Science & MathematicsPhysics · 9 years ago

PHYSICS: how would you do these questions? Please and thank you!!! 10 points?

1) An airplane covers 340 km in 1.9 hours. What is its average speed?

2) A truck increases its speed from 10 m/s to 30 m/s over a distance of 50 m in 4 seconds. What is the acceleration of the truck?

3) A runner travels 650 m at a steady speed of 5.96 m/s. The time taken to travel the 650 m is ________.

4) A hockey player, gliding over the ice at a speed of 12 m/s, accelerates at -2.3 m/s2 for 3.3 s. His final speed is ________.

5) A car travels 14.0 kilometers due south and then 18.0 kilometers due east going from town A to town B. What is the approximate magnitude of the displacement of a helicopter that flies in a straight line from town A to town B?

Update:

I want to understand how to do the problems not just the answer. If you just give me the answer I dont learn anything

3 Answers

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  • Anonymous
    9 years ago
    Favorite Answer

    1.speed=distance/time but you need to convert the km into m ant hours into seconds

    2. acceleration=change in velocity/time

    3.Again speed=distance/time rearrange for time

    4. v=u+at where v=final velocity u=inital velocity

    5.pythagoras' theorem: if you draw the travel of the car south and then east you get a right angle triangle then a^2+b^2=c^2

  • 9 years ago

    1) This is simply speed, distance and time. The equation for this is: Speed = distance ÷ time. So if the airplane has covered 340 km (distance) you divide it by the time taken (1.9 hours). So speed = 340 ÷ 1.9 = 178.947 km/h

    2) The equation for acceleration is: Acceleration = change in velocity ÷ time taken for change. More detailed: a = (v2 - v1) ÷ t where v2 is the final velocity, v1 is the initial velocity and t is the time taken. So for the truck: a = (30 - 10) ÷ 4, a = 5 metres per second² (m/s²)

    3) Again speed distance time. So for the runner: 5.96 = 650 ÷ time, but we need to re-arrange this to get time so we divide 650 by 5.96 which gives us 109.06 minutes or basically 1 hour and 9 minutes

    4) A negative value for acceleration is basically deceleration but we still use the same formula only this time we need to re-arrange it to get the final speed. So for the hockey player: -2.3 m/s² = (v2 - 12) ÷ 3.3, re-arranged to (by multiplying out the division): -2.3 x 3.3 = v2 - 12, re-arranged to (by adding 12 to both sides): -2.3 x 3.3 + 12 = v2. So The final speed is 4.41 m/s

    5) This is magnitude of displacement, something I haven't really learnt but I'm willing to give it a go...

    I believe for 2 dimensions the formula would be: sqrt( x² + y²) so for the car it's: sqrt(14² + 18²) so the magnitude of displacement for a helicopter that flies in a straight line from town A to town B is 22.8 metres (rounded to 1 decimal place).

    Hope this all helped! :D

    Source(s): My brain & some quick research on magnitude of displacement.
  • 4 years ago

    a million) i might use vector addition and understand that i'm able to use the Pythagorean theorem to discover the cost of the consequent vector. 2) Conservation of linear momentum. pi = pf pi = m1v1 + m2v2, v2 = 0, so pi = m1v1, pf = (m1 + m2)vf Equate and remedy for m2. 3) Their circumstances have been bunched collectively, which skill precise, yet they neglected the easily time by using roughly .26secs, so no longer precise. 4) Conservation of total potential. placing preliminary means potential to be 0 on the floor, the preliminary total potential = preliminary Kinetic potential which = (a million/2)mv^2. while the ball reaches fabulous top, very final Kinetic potential = 0, so total potential = very final means potential. for the reason that total potential is conserved, preliminary Kinetic potential = very final means potential The replace in means potential = - replace in Kinetic potential 5) i might use W = Fx and upload the different strikes collectively. the 1st action is the strain the boy applies circumstances the gap the container travels. the 2d action is the load of the container circumstances the top it is lifted. 6) i might use the Impulse-Momentum courting: replace in Momentum = Impulse = tension x replace in Time 7) Use the equation GMm/r^2. If the two hundreds are doubled, M will become 2M, and m will become 2m. If the the gap is likewise doubled, r will become 2r, so r^2 will become 4r^2. The coefficients cancel out and you get an identical internet tension. 8) They the two hit the floor on an identical time by way of fact the vertical area of acceleration are the two an identical.

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