Physics 103 Exam

1. A 2.5 kg mass falls from rest to the ground from a 3m high roof.What is the kinetic energy of the mass just before it strikes the ground?

29.5J

75J

24.6J

750J

2. Young's Modulus of nylon is 510⁹ N/m². A force of 510⁵ N is applied to a 4 meter length of nylon of cross sectional area of 0.1m². By how much does the nylon stretch ?

4*10^-3 m

2*10^-2 m

2*10^-3 m

4*10^-2 m

3. A parallel –plate capacitor has a plate area A=1*10^-4m² if filled with vacuum and separated by 1mm and is connected to a battery of voltage =10V , what is the charge on each plate ?

0.8C

45nC

22nC

8.85PC

4. What is the electric potential at a distance of 5mm from an electron ?

-2.9*10^-7 V

-2.2*10^-9 V

3.0*10^-7 V

3.6*10^9 V

5. In a parallel plate capacitor , what will happen to C if the space between the two plates doubled ?

C=Co

C=2Co

C=1/2Co

C=3/2Co

6. With one violin playing, the sound level at a certain place is measured as 50 dB. If four violins play equally loudly, what will the sound level most likely be at this place?

56 dB

70 dB

20dB

45 dB

7. In the figure, what is the net force on q₂ if q₁=80µC, q₂= -200µC and q₃= 60µC?

21.2N

31.4N

9.7N

15.7N

8. What is the energy stored in 250µF capacitor if it is charged with 10V battery ?

5*10^-2 J

2.5*10^-2 J

8*10^-2

1.3*10^-2 J

9. Two balloons are charged with an identical quantity and type of charge: -6.25 nC. They are held apart at a separation distance of 61.7 cm. Determine the magnitude of the electrical force of repulsion between them ?

9.23 x 10^-7 N

2.23 x 10^-5 N

9.23 x 10^-5 N

22.3 x 10^-7 N

10. A ball is thrown straight up with an initial velocity of 23m/s from the ground level. What is the ball's velocity after 3s?

17m/s, downward

7m/s, upward

7m/s, downward

17m/s, upward

11. A particle of charge q₁=+6µC is located on the x-axis at the point x₁=5.1cm . A second particle of charge q₂=-5µC is placed on the x-axis at x₂= -3.4cm. What is the electric potential at the origin (x=0)?

1.3*10^3 V

-2.64*10^5 V

-1.3*10^3 V

2.64*10^5 V

12. If the position of a particle is X=2t³– 5, what is the average acceleration between t=1s and t=2s?

18 m/s^2

27 m/s^2

12m/s^2

9m/s^2

13. A student of mass 40 kg is now standing on a weighting machine in an elevator (Take g= 10m/s^-2 ).What is the acceleration (magnitude and direction) of the student if the reading on the weighing machine is 450 N?

3.1m/s^2, upward

1.25m/s^2, downward

3.1m/s^2, downward

1.25m/s^2,upward

14. The electric field between two parallel plates capacitor is 250N/C and the separation between the plates is 40 m. If an electron is released from rest at the negative plate what will be its speed as it hits the positive plate? (m_e=9.11*10^-31) ?

2.7*10^6m/s

59.2*10^6m/s

17.5*10^6m/s

29.6*10^6m/s

15. Two point charges q₁=+7µC and q₂=+10µC are located along x-axis separated by 2m .where should a 3^rdnegative charge be placed such that the net electric force on it is ZERO ?

0.9m from q1

0.9m from q2

1m from q1

0.4 from q1

16. What is the required force to keep 2*10^-5 m³ cube of ice completely submerged in fresh water ? (Density of ice is 920kg/m³, density of fresh water is 1000kg/m³⁾

8*10^-3 N

4*10^-3 N

16*10^-3 N

32*10^-3 N

17. What is the angle between vector C=A+B and the positive x-axis if A=i-3j and B=2i+j?

30°

157°

233°

326°

18. At what distance from a negative charge of 5.536 nC would theelectric field strength be 1.90 x 105 N/C ?

1.6 cm

2.5cm

5cm

8.3cm

19. A 20 kg block is placed over a massless rod of length 1m that is supported by two ropes as shown in the figure. What is the tension in the right rope (T₂) if the distance d=0.25m ?

200N

50N

100N

150N

20. Given Ө=25° an incline has a mass of 20 kg placed upon it . It is attached by a rope over a pulley to a mass of 30 kg which hangs vertically. The coefficient of friction is 0.2. The acceleration will be :

7 m/s^2

3.5 m/s^2

2 m/s^2

7.3 m/s^2

Physics 103 Exam

1. A 2.5 kg mass falls from rest to the ground from a 3m high roof.What is the kinetic energy of the mass just before it strikes the ground?

2.

What first name or nickname would you like us to use?

2. Young's Modulus of nylon is 5*109 N/m2. A force of 5*105 N is applied to a 4 meter length of nylon of cross sectional area of 0.1m2. By how much does the nylon stretch ?

3. A parallel –plate capacitor has a plate area A=1*10-4 m2 if filled with vacuum and separated by 1mm and is connected to a battery of voltage =10V , what is the charge on each plate ?