Basic Physics I:  Sample Final Exam

Put each question on a separate page and SHOW YOUR WORK!

No electronic devices except for a non-programmable calculator

Short Answer:  12 points each

1.         A vector has components Ax = -6m and Ay = 8m.  Find the magnitude of the vector and the angle, q, it makes with the positive x axis.  Sketch the vector in your bluebook.

2.     Two rods are connected together and to an axle about which they can rotate.  Rod 1 makes an angle of 53o with the horizontal and Rod 2 an angle of 30o.  F1 = 20N in the vertical direction and acts on the end of Rod 1.  F2 = 10N in the horizontal direction and acts on the end of Rod 2.  What is the net torque about the axis of rotation?  (Indicate whether it is clockwise or counterclockwise.)

 

3.     A car is moving to the right with a speed of 30m/s.  It slows to a speed of 10m/s in 8s.  What was its acceleration?  (Give the Magnitude and Direction.)

 

 

 

4.     A tube, sealed at one end, sits with its open end in a bowl of mercury.  The air pressure at the top of the tube is 104Pa when a column of mercury has risen 0.6m up the tube.  What is the air pressure outside, i.e. above the bowl of mercury?  (The density of mercury is 13,600kg/m3.)

 

 

 

 

 

 

Problems (20 points each)

5.     A 3kg mass is on a level frictionless surface and attached to a spring of force constant 300N/m.  At one instant the mass has a speed of 2m/s and the spring is compressed 0.1m.  As the mass and spring system oscillates, what will be the maximum speed of the mass?

6.     If I hang a Mass M on a spring, the frequency of oscillation is 3Hz.  If I add 0.5kg to the mass M the new frequency of oscillation is 2Hz.  Find the original mass M and the spring constant.

7.     I have a density of 103kg/m3.  I am standing surrounded by air of density 1.3 kg/m3.  If my mass is 70kg, what is the buoyant force the air exerts on me? 

 

8.     A box, M2, is on a frictionless incline plane of angle q = 30o.   There is a string attached to the box and goes parallel to the surface of the incline plane and over a frictionless pulley to another mass M1 = 2kg.  M1 has a downward acceleration of 4m/s2.

a)     Draw the force diagram for each box, showing all the forces acting on them. 

b)     What do you know about the tensions T1 and T2? 

c)     Write down Newton’s Laws for each box and find M2.

 

 

 

9.       I have a block of wood of density 600kg/m3 and a volume of 1.5m3.  If I place a lead weight of mass 100kg on top of the wood, how much, i.e. what volume, of the wood will be under water, Dwater = 1000kg/m3?  (Hint:  how much water must it displace?)