Part -1:
1. How much force does a 20 000-kg rocket develop to accelerate 1-m/s2?
2. If the force of friction acting on a sliding crate is 100-N, how much force must be ap-plied to maintain a constant velocity? What will be the net force acting on the crate? What will be the acceleration?
3. Calculate the acceleration of a 2000-kg, sin-gle-engine airplane just before takeoff when the thrust of its engi ne is 500 N.
4. Calculate the acceleration of a 300 000-kg jumbo jet just before takeoff when the thrust for each of its four engines is 30 000-N.
a Calculate the acceleration if you push with a 20-N horizontal force on a 2-kg block on-a horizontal friction-free air table.
b What acceleration occurs if the friction force is 4-N?
5. Calculate the horizontal force that must be applied to a 1-kg puck to make it accelerate on a horizontal friction-free air table with the same acceleration it would have if it were dropped and fell freely.
6. Calculate the horizontal force that must be applied to produce an acceleration of 1.8-g for a 1.2-kg puck on a horizontal friction-free air table.
7. If a 1-N net force accelerates a 1-kg mass at l-m/s2, what is the acceleration caused by a net force of 2-N on a 2-kg mass?
What is the acceleration of a 747 jumbo jet, mass 30 000-kg, in takeoff when the thrust for each of its four engines is 30 000-N?
8. A certain force applied to a 2-kg mass accel-erates the mass at 3-m/s2. How much accel-eration will the same force produce on a 4-kg mass?
9. If a four-engine jet accelerates down the runway at 2-m/s2 and one of the jet engines fails, how much acceleration will the other three produce?
10. If a loaded truck that can accelerate at 1-m/s2 loses its load and has three-fourths of the original mass, what acceleration can it attain from the same driving force?
11. An occupant of a car has a chance of surviving a crash if the acceleration during the crash is not more than 30-g. Calculate the force on a 70-kg person accelerating at this rate.
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Lt. Col. John L. Stapp set the land speed record of 632-mph (284-m/s) in an experimental rocket sled, Sonic Wind, at the Holloman Air Base Development Center, Alamogordo, New Mexico, on in 1954. Running on rails and propelled by nine rockets, the sled reached its top speed within 5-s. And it slowed to rest during a time interval of 1.4-s.
a Find the average acceleration in reaching maxi mum speed.
b How far did the sled travel before at-taining maxi mum speed?
c Find the stopping distance.
d Determine the magnitude of the force applied to Stapp's 74-Kg body as the sled came to rest.
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The Gemini program, in preparation for the Apollo missions, tested many procedures used during the Apollo moon flights. One of the more important was docking. As part of this procedure on 12 Sep 66 a Gemini spacecraft, mass 3400-Kg, eased into an or-biting Agena rocket casing. The aft thrust¬ers were ignited, 890-N of thrust for 7.0-s, accelerating both the Gemini and Agena space crafts. The magnitude of the change in the velocity for the two together was 0.93- m/s. Use these data to compute the mass of the Agena casing.
14. Find the magnitude of the applied force re-quired to accelerate a 450-Kg rocket sled on fixed rails from a standing start to a speed 6.0-m/s in 30-s. The retarding force of fric-tion is 93-N.
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A 10-kg bucket of water is lowered by a rope applying 30-N of tension. Compute the acceleration of the bucket.
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A 100-Kg rocket is moving directly upward when the engine is fired.
a Compute the thrust when the accelera¬tion is 12-m/s2T.
b Compute the acceleration when the thrust is 800-N T.
c Compute the thrust when the speed is a constant 5.0-m/s T.
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A 70-kg thief tries to escape from a 3rd sto-ry, 15-m, jail cell window by tying together bed sheets. The maximum tension the sheets can support is 500-N. Compute the mini¬mum speed of the thief when he makes con¬tact with the ground.
18. A 10-kg mass on a horizontal friction-free air track is accelerated by a string attached to another 10-kg mass hanging vertically from a pulley as shown.
What is the force due to gravity in newtons of the hanging 10-kg mass? What is the ac-celeration of the system of both masses?
19.
Suppose the masses described in the preced-ing problem are 1-kg and 99-kg, respectively.
a Compare the accelerations when they are interchanged, that is, for the case where the 1-kg mass dangles over the pulley, and then
b for the case where the 100-kg mass dangles over the pulley.
c What does this indicate about the max-imum acceleration of such a system of masses?
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The horse pulling the cart is a classic problem in physics. Generations of physics stu¬dents have addressed this one. We all know a horse can pull a cart. The horse applies a force to the cart. That means the cart applies a force to the horse. How does the horse force applied to the cart compare to the cart force applied to the horse? Considering this how can a horse accelerate a cart from rest to common horse walking speed?
Part -2:
Worksheet
1. What is meant by the net force that acts on an object?
2. Suppose a cart is being moved by a certain net force. If the net force is doubled, by how much does the cart's acceleration change?
3. Suppose a cart is being moved by a certain net force. If a load is dumped into the cart so its mass is doubled, by how much does the acceleration change?
4. State Newton's second law in words and then in the form of an equation.
5. How much force does a 20000 kg rocket develop to accelerate 1m/s2?
6. If the force of friction acting on a sliding crate is 100 N , how much force must be applied to maintain a constant velocity? What will be the net force acting on the crate? What will be the acceleration?
7. Calculate the acceleration of a 2000 kg , single-engine airplane just before takeoff when the thrust of its engine is 500 N .
8. Calculate the acceleration of a 300000 kg jumbo jet just before takeoff when the thrust for each of its four engines is 30000 N .
9. Calculate the acceleration if you push with a 20 N horizontal force on a 2 kg block on a horizontal, friction-free air table.
10. What acceleration would the block in question 9 have if there were a 4 N frictional force?
11. Calculate the horizontal force that must be applied to a 1 kg puck to make it accelerate on a horizontal, frictionless air table with the same acceleration it would have if it were dropped and fell freely ( 9.8 m/s2).
12. Calculate the horizontal force that must be applied to produce an acceleration of 17.6 m/s2 for a 1.2 kg puck on a horizontal, frictionless air table.
13. If an object has no acceleration, can you conclude that no forces are exerted on it? Explain.
14. If a 1 N net force accelerates a 1 kg mass at 1 m I s2 , what is the acceleration caused by a net force of 2 N on a 2 kg mass?
15. What is the acceleration of a 747 jumbo jet, mass 30000 kg , in takeoff when the thrust for each of its four engines is 30000 N ?
16. A certain force applied to a 2 kg mass accelerates the mass at 3m/s2 . How much acceleration will the same force produce on a 4 kg?
17. A horizontal force of 100 N is required to push a crate across a factory floor at a constant speed. What is the net force acting on the crate? What is the force of friction acting on the crate?
18. If a four engine jet accelerates down the runway at 2m/s2 and one of the jet engines fails, how much acceleration will the other three produce?
19. If a loaded truck that can accelerate at 1m/s2 loses its load and has three-fourths of the original mass, what acceleration can it attain from the same driving force?
20. An occupant of a car has a chance of surviving a crash if the deceleration during the crash is not more than -294 m/s2. Calculate the force on a 70 kg person decelerating at this rate.