PSC Questions #4 Newton’s Laws
1. A 600 N object is to be given an acceleration of 0.70 m/s2. How large an unbalanced force must act upon it?
2. A 4.50 kg toy car undergoes acceleration in a straight line along the x-axis. The figure below shows this acceleration as a function of time.
a. Find the maximum net force on this cart and state when this maximum force occurs?
b. During what times is the net force on the cart constant?
c. When is the net force equal to zero?
3. A book sits on a table in equilibrium.
a. What forces act on it?
b. What is the reaction force to each of the forces acting on the book?
c. What are the action-reaction pairs? (Use diagrams to explain this)
4. A 75.0 kg person stands on a weighing scale in an lift. What does the scale read when:
a. the lift is at rest?
b. the lift is climbing at a constant speed of 3.0 m s-1?
c. the lift is falling at 3.0 m s-1?
d. the lift is accelerating upward at 3.0 m s-2?
e. the lift is accelerating downward at 3.0 m s-2?
5. In the figure shown below, friction and the mass of the pulley are both negligible. Find the acceleration of m2 if m1= 300 g, m2 = 500 g, and F = 1.5 N.
6. The distance between two telephone poles is 50 m. When a 1 kg bird lands on the telephone wire halfway between the poles, the wire sags (i.e. goes down) 0.2 m.
a. Draw a free body diagram of the bird.
b. How much tension does the bird produce in the wire?
7. A woman at the airport is towing her 20 kg suitcase at constant speed by pulling on a strap at an angle of θ above the horizontal. She pulls the strap with a force of 35 N and the frictional force on the suitcase is 20 N.
a. What is the angle θ that the strap makes with the horizontal?
b. What normal force does the ground exert on the suitcase?
8. *Three masses are connected on a table as shown below. The table has a coefficient of sliding friction of 0.35. The three masses are 4.0 kg, 1.0 kg, and 2.0 kg, respectively and the pulleys are frictionless.
a. Determine the acceleration of each block and their directions.
b. Determine the tensions in the two cords.
Дата добавления: 2015-11-04; просмотров: 14 | Нарушение авторских прав
| <== предыдущая лекция | | | следующая лекция ==> |
| Акселератор Дружбы– комфортная среда для роста вашего бизнеса | | | 1. State two conditions that must be satisfied for the static equilibrium to take place. Does it matter which point you choose as the pivot point about which you calculate all torques? |