physics

A motorist increase speed from rest and in 21s reaches am a speed of 20km/hr.What is (a)the uniform acceleration in ms-2?(b)the distance covered in the time interval?

  1. 👍 0
  2. 👎 0
  3. 👁 184
  1. Just dust off your good old formulas:

    v = at
    s = 1/2 at^2

    First, get better units:

    20 km/hr * 1000m/km * hr/3600sec = 5.555m/s

    Velocity changed from 0 to 5.555m/s in 21s.

    v = at
    5.555 = 21a
    a = 0.265m/s^2

    s = .5at^2 = .5*0.265*21^2 = 58.43m

    1. 👍 0
    2. 👎 0

Respond to this Question

First Name

Your Response

Similar Questions

  1. Physics

    A motorist travels 160km at 80km/hr and 160km at 100km/hr. What is the average speed of the motorist for this trip? I need the step by step solution because I didn't listen to ny teacher properly

  2. Physics

    A motorist traveling with a constant speed of 15m/s passes a school-crossing corner, where the speed limit is 10m/s. Just as the motorist passes, a police officer on a motorcycle at the corner starts off in pursuit with constant

  3. Physics

    A constant force is exerted for a short time interval on a cart that is initially at rest on an air track. This force gives the cart a certain final speed. Suppose we repeat the experiment but, instead of starting from rest, the

  4. physics, dynamics

    Car A starts from rest at t = 0 and travels along a straight road with a constant acceleration of 2 m/s2 until it reaches a speed of 27 m/s. Afterwards it maintains this speed. Also, when t = 0, car B located 2000 m down the road

  1. physics

    A motorist drives along a straight road at a constant speed of 15.0 m/s. Just as she passes a parked motorcycle police officer, the officer starts to accelerate at 2.00 m/s2 to overtake her. Assuming the officer maintains this

  2. physics

    An object starts from rest and accelerates uniformly down an incline. If the object reaches a speed of 40 m/s in 5 seconds, what is its average speed?

  3. physics

    A motorist drives along a straight road at a constant speed of 15.0 m/s. just as she passes a parked police officer,the officer starts to accelerate at 2.00 m/s^2 to overtake her. assuming the officer maintains this acceleration,

  4. physics

    A motorist drives along a straight road at a constant speed of 15.0 m/s. just as she passes a parked police officer,the officer starts to accelerate at 2.00 m/s^2 to overtake her. assuming the officer maintains this acceleration,

  1. Physics

    A girl starts from rest and reaches a walking speed of 1.4 m/s in 3.0 s. She walks at this speed for 6.0 s. Girl then slows down and comes to a stop during a 10.0 -s period. What was her acceleration during each of the 3 time

  2. physics

    A 4.00-m length of light nylon cord is wound around a uniform cylindrical spool of radius 0.500 m and mass 1.00 kg. The spool is mounted on a frictionless axle and is initially at rest. The cord is pulled from the spool with a

  3. physics

    A daredevil on a motorcycle leaves the end of a ramp with a speed of 29.5 m/s as in the figure below. If his speed is 27.1 m/s when he reaches the peak of the path, what is the maximum height that he reaches? Ignore friction and

  4. physics(kinematics)

    A police officer in a patrol car parked in a 70 Km/h speed zone observes a passing automobile might be intoxicated,the officer starts his car,accelerates uniformly to 90 Km/h in 8s ,and maintaining a constant velocity of 90

You can view more similar questions or ask a new question.