A force of 9 pounds stretches a spring 1 foot. A mass weighing 6.4 pounds is attached to the spring, and the system is then immersed in a medium that offers a damping force numerically equal to 1.2 times the instantaneous velocity. Find the equation of motion If the mass is initially released from rest from a point 1 foot above the equilibrium position.

When the velocity of an object is doubled, by what factor is its momentum changed? by what factor is its kinetic energy changed? a) the momentum is zero. b) the momentum is not zero. c) difficult to say.

Consider an ordinary, helium-filled party balloon with a volume of 2.2 ft3. the lifting force on the balloon due to the outside air is the net resultant of the pressure distribution exerted on the exterior surface of the balloon. using this fact, we can derive archimedes’ principle, namely that the upward force on the balloon is equal to the weight of the air displaced by the balloon. assuming that the balloon is at sea level, where the air density is 0.002377 slug/ft3, calculate the maximum weight that can be lifted by the balloon. note: the molecular weight of air is 28.8 and that of helium is 4.

This is important. 1. which of the following is an si base unit for measuring length? (2 points) inch gram meter mole 2. which of the following units for distance is an si unit? (2 points) centimeter foot inch yard 3. which of the following tools should a scientist use to measure an object in meters? (2 points) electronic balance pan balance tape measure thermometer