Assignment:
1. A force F = 75.8N is pulling on a box as shown. The box weighs at 198N, and was placed " on a rough surface. At the contact, the static and kinetic friction coefficients are μs, = 0.482 and μk = 0.412 respectively.
a) Please draw a free body diagram for the box; identify and label all forces; and select a coordinate system.
b) Please use your calculation to determine whether the force is sufficient to move the box. if it is not sufficient, what should be the minimum force to move the box? If it is sufficient, what is the magnitude of the box's acceleration?
2. 150g of ice of initial temperature -10.0°C is stored in a container. Certain amount of water steam at initial temperature 100.0°C is directed into the container. After thermal equilibrium is reached, there is only water of temperature 50.0°C left in the container. Please determine how many grams of steam is used in this process. During the process, the ice-steam mixture loses 5.00 * 103J of heat to the container and the surroundings.
3. A sphere of mass m = 0.348kg and radius r = 0.437m is spinning around its central axis as shown. If the kinetic energy of the sphere is 47.3J , what is its angular speed?
4. A stone is thrown up at an angle 34.7° above horizontal, and 5.4 is later, it reaches the highest point of its trajectory. What is the magnitude of the launching velocity?
5. Which of the following statements is (are) true?
I. When an object is in mechanical equilibrium state, it must experience no acceleration.
II. When two objects in contact reach thermal equilibrium, each of them must store the same amount of heat.
(a) Only I is true.
(b) Only II is true.
(c) Both I and II are true,
(d) Neither I nor II is true.
6. Three forces, F1, = 2.34iN, F2 = 1.57jN and F3 = (-3.46i+ 0.584j 1.99k)N are applied on a box. What is the magnitude of the net force on the object?
(a) 3.02N
(b) (-1.12i + 2.15j + 1.99k)N
(c) 3.14N
(d) 4.2N
7. Which of the following statements is true regarding an object completely submerged under water?
I. When at greater depth, the object must experience greater pressure force.
II. When at greater depth, the object must experience greater buoyant force since the pressure force on it is greater.
(a) Only I is true.
(b) Only II is true.
(c) Both I and II are true.
(4) Neither I nor II is true.
8. Which of the following statements is (are) true regarding two force, F1 and F2 (F1 > F2), acting on a rod?
I. F1 must exert greater torque on the rod than F2 does.
II. F1 must do more work to the rod than F2 does.
III. F1 must exert greater pressure on the rod tham F2 does.
(a) Only I is true.
(b) Only I and II are true.
(c) Only I and III are true.
(d) None of them is true.
9. Which of the following statements is true regarding two objects of different temperature?
(a) The one of higher temperature must store more heat.
(b) The one of higher temperature must store more thermal energy.
(c) The one of higher temperature must have greater specific heat capacity.
(d) None of the above is true.
10. Which of the following statements is (are) true?
I. When there is only conservative force acting on an object, the linear momentum of object does not change.
II, When there is only conservative force doing work on an object, the potential energy of the object does not change.
(a) Only I is true.
(b) Only II is true.
(c) Both I and II are tre
(d) Neither I nor II is true.