Concept #1: Newton's Second Law Revisited

A sled filled with sand slides without friction down a 38° slope. Sand leaks out a hole in the sled at a rate of 2.1 kg/s. If the sled starts from rest with an initial total mass of 41.0 kg, how long does it take the sled to travel 130 m along the slope?

A child pulls a wagon behind her when it starts to rain. If the wagon is collecting 10 mL of water per second, with what force does she have to pull the wagon to keep it moving at 1.5 m/s?

A 15 kg object moves along a path given by x(t) = 3m - (1.7 m/s)t + (0.7 m/s3)t3. (a) What is the object's momentum as a function of time?(b) What is the force (as a function of time) acting on the object?

A particle of mass m is at rest at t = 0. Its momentum for t > 0 is given by p x = 6t2 kg•m/s, where t is in s. Find an expression for Fx(t), the force exerted on the particle as a function of time.