Part A ReviewI Constants Periodic Table In researching the forces that act on flying birds scientists studied the motion of cockatiels' bodies as they fly in horizontal flight. As the birds beat their wings, their bodies move up and down. (Figure 1) shows the vertical acceleration of a cockatiel's body during one wing beat, consisting of an upstroke followed by a downstroke If the bird's mass is 82 g, what is the maximum net vertical force exerted on the bird? Express your answer with the appropriate units. F-2.95 SubmitPn Previous Answers Request Answer X Incorrect; Try Again; 5 attempts remaining Figure 1 of 1 Part B "y (m/s2) 50 The bird is held in level flight due to the force exerted on it by the air as the bird beats its wings. What is the maximum value of this force due to the air? Note that the bird's weight, the force of gravity acting on it, is calculated using w mg, a result that will be justified in Chapter 5 Express your answer with the appropriate units. 0 I-t (s) 0.02 0.06 0.08 0.10 50 (FairxValue Units Upstroke Downstroke Submit Request Answer

The wheels of a midsize car exert a force of 2100 N backward on the road to accelerate the car in the forward direction. If the force of friction including air resistance is 250 N and the acceleration of the car is 1.80 m/s2, what is the mass of the car plus its occupants? Explicitly show how you follow the steps in the Problem-Solving Strategy for Newton's laws of motion. For this situation, draw a free-body diagram and write the net force equation.

. A person stands on a scale inside an elevator at rest (Figure 2.54). The scale reads 800 N. (a) What is the person's mass? (b) The elevator accelerates upward momentarily at the rate of 2 m/s2. What does the scale read then? (c) The elevator then moves with a steady speed of 5 m/s. What does the scale read now?

A 10-lb rock and a 1-lb rock are dropped simultaneously from the same height. (a) Some say that because the 10-lb rock has 10 times as much force acting on it as the 1-lb rock, it should reach the ground first. Do you agree? (b) Describe the situation if the rocks were dropped by an astronaut on the Moon.

Which statement is correct? (a) Net force causes motion. (b) Net force causes change in motion. Explain your answer and give an example.

Jogging on hard surfaces with insufficiently padded shoes produces large forces in the feet and legs. (a) Calculate the magnitude of the force needed to stop the downward motion of a jogger's leg, if his leg has a mass of 13.0 kg, a speed of 6.00 m/s, and stops in a distance of 1.50 cm. (Be certain to include the weight of the 75.0-kg jogger's body.) (b) Compare this force with the weight of the jogger.

A flea jumps by exerting a force of 1.2010-5Nstraight down on the ground. A breeze blowing on the flea parallel to the ground exerts a force of 0.50010-6Non the flea while the flea is still in contact with the ground. Find the direction and magnitude of the acceleration of the flea if Its mass is 6.0010-7kg . Do not neglect the gravitational force.

The device shown below is the Atwood’s machine considered in Example 6.5. Assuming that the masses of the string and the frictionless pulley are negligible, (a) find an equation for the acceleration of the two blocks; (b) find an equation for the tension in the string; and (c) find both the acceleration and tension when block 1 has mass 2.00 kg and block 2 has mass 4.00 kg.

A 0.450-kg hammer is moving horizontally at 7.00 m/s when it strikes a nail and comes to rest after driving the nail 1.00 cm into a board. Assume constant acceleration of the hammer-nail pair. a. Calculate the duration of the impact. b. What was the average force exerted on the nail?

In Section 2.4, we computed the force needed to accelerate a 1,000-kg car from 0 to 27 m/s in 10 s. Compute the force using the alternate form of Newton’s second law. The change in momentum is the car’s momentum when traveling 27 m/s minus its momentum when going 0 m/s.