A boy falls off his bike and hits his head (5 kg) on the pavement. The velocity of his fall at the time of impact is 5 m/s. (p = m v) The helmet slowed the impact to 0.001 s. What is the force felt on the boy's brain due to his fall?
(F Δt = m Δv => F = (m Δv)/Δt )

Remember to report your units.

If the boy in problem 5 had not been wearing his helmet, how much force would have been applied to his brain during the collision? (Δt = 0.000001 s without a helmet. )

How do we measure or think of speed in the united states?

What is the weight of a 8-kg substance in n, kn, kg·m/s2, kgf, lbm·ft/s2, and lbf?

Consider a uniformly charged ring in the xy plane, centered at the origin. the ring has radius a and positive charge qdistributed evenly along its circumference. a)what is the direction of the electric field at any point on the z axis? . b)what is the magnitude of the electric field along the positive z axis? use k in your answer, where k=14πϵ0. d)the ball will oscillate along the z axis between z=d and z=−d in simple harmonic motion. what will be the angular frequency ω of these oscillations? use the approximation d≪a to simplify your calculation; that is, assume that d2+a2≈a2. express your answer in terms of given charges, dimensions, and constants