applied mechanics

posted by .

a motorist driving his car at a speed of 72km/hr observes that the traffic lights ahead of him turns red if he comes to a halt at the traffic light 5seconds starting from first find the distance of the car from the light when the motorist observed the red light

  • applied mechanics -

    Vo = 72000m/3600s = 20 m/s.

    V = Vo + a*t = 0.
    20 + a*5 = 0, a = -4 m/s^2.

    V^2 = Vo + 2a*d.
    V = 0, Vo = 20 m/s, a = -4 m/s^2,
    d = ?.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Physics

    A car is going 20m/s when they see a traffic light 200m ahead turn red. The traffic light is known to stay red for 15s. The driver wants to reach the light as it turns green. It takes them 1s to press the breaks and the car slows down …
  2. Physics

    You are driving a 2570.0-kg car at a constant speed of 14.0 m/s along a wet, but straight, level road. As you approach an intersection, the traffic light turns red. You slam on the brakes. The car's wheels lock, the tires begin skidding, …
  3. Physics

    You are driving a 2570.0-kg car at a constant speed of 14.0 m/s along a wet, but straight, level road. As you approach an intersection, the traffic light turns red. You slam on the brakes. The car's wheels lock, the tires begin skidding, …
  4. Physics

    You are driving a 2570.0-kg car at a constant speed of 14.0 m/s along a wet, but straight, level road. As you approach an intersection, the traffic light turns red. You slam on the brakes. The car's wheels lock, the tires begin skidding, …
  5. physics 1

    You are driving your car, and the traffic light ahead turns red. You apply the brakes for 2.13 s, and the velocity of the car decreases to +4.90 m/s. The car's deceleration has a magnitude of 3.55 m/s2 during this time. What is the …
  6. PHYSICS

    You are driving your car and the traffic light ahead turns red. You applied the brake for 3.00 seconds and the velocity of the car decreases to 4.50 m/s. The car's deceleration has a magnitude of 2.70 m/s^2 during this time. What is …
  7. Physics

    You are driving a 2530.0-kg car at a constant speed of 14.0 m/s along a wet, but straight, level road. As you approach an intersection, the traffic light turns red. You slam on the brakes. The car's wheels lock, the tires begin skidding, …
  8. phys

    A motorist is driving at 20m/s{\rm m/s} when she sees that a traffic light 200m{\rm m} ahead has just turned red. She knows that this light stays red for 15s{\rm s} , and she wants to reach the light just as it turns green again. It …
  9. physics

    A motorist is driving at 20m/s{\rm m/s} when she sees that a traffic light 200m{\rm m} ahead has just turned red. She knows that this light stays red for 15s{\rm s} , and she wants to reach the light just as it turns green again. It …
  10. Physics

    You are driving your car, and the traffic light ahead turns red. You apply the brakes for 2.28 s, and the velocity of the car decreases to + 4.76 m/s. The car’s deceleration has a magnitude of 2.99 m/s2 during this time. What is …

More Similar Questions