Un niño juega con una pelota unida a un hilo elástico. Si se estira 50 cm cuando el niño le ejerce una fuerza de 4 N, ¿cuánta fuerza deberá aplicar el niño para que el hilo se estire 65 cm?

Which sound characteristic is not affected by the relative motion of an object

What kind of waves require a medium to travel? question 6 options: light waves mechanical waves all waves need a medium to travel electromagnetic waves

You are driving to the grocery store at 20 m/s. you are 110m from an intersection when the traffic light turns red. assume that your reaction time is 0.50s and that your car brakes with constant acceleration. how far are you from the intersection when you begin to apply the brakes? what acceleration will bring you to rest right at the intersection? how long does it take you to stop after the light changes? the known values: vi=20m/s xi=110m t=.50s vf=0m/s xf=0m a=?