Physics 103 Exam

Question 1

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

Accepted Answer

326°

Answer

30°

Answer

157°

Answer

233°

Question 2

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

Accepted Answer

7m/s, downward

Answer

17m/s, downward

Answer

7m/s, upward

Answer

17m/s, upward

Question 3

If the position of a particle is X=2t3 &ndash; 5, what is the average acceleration between t=1s and t=2s?

Accepted Answer

18 m/$$s^2$$

Answer

27 m/$$s^2$$

Answer

12m/$$s^2$$

Answer

9m/$$s^2$$

Question 4

Given Ө=25&deg; 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 :

Accepted Answer

3.5 m/$$s^2$$

Answer

7 m/$$s^2$$

Answer

2 m/$$s^2$$

Answer

7.3 m/$$s^2$$

Question 5

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?

Accepted Answer

1.25m/$$s^2$$,upward

Answer

3.1m/$$s^2$$, upward

Answer

1.25m/$$s^2$$, downward

Answer

3.1m/$$s^2$$,  downward

Question 6

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?

Accepted Answer

75J

Answer

29.5J

Answer

24.6J

Answer

750J

Question 7

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 ?

Accepted Answer

150N

Answer

200N

Answer

50N

Answer

100N

Question 8

Young&rsquo;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 ?

Accepted Answer

4*10^-3 m

Answer

2*10^-2 m

Answer

2*10^-3 m

Answer

4*10^-2 m

Question 9

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)

Accepted Answer

16*10^-3 N

Answer

8*10^-3 N

Answer

4*10^-3 N

Answer

32*10^-3 N

Question 10

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?

Accepted Answer

56 dB

Answer

70 dB

Answer

20dB

Answer

45 dB

Question 11

what is the energy stored in 250&micro;F capacitor if it is charged with 10V battery ?

Accepted Answer

1.3*10^-2 J

Answer

5*10^-2 J

Answer

2.5*10^-2 J

Answer

8*10^-2

Question 12

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 ?

Accepted Answer

9.23 x 10^-7 N

Answer

2.23 x 10^-5 N

Answer

9.23 x 10^-5 N

Answer

22.3 x 10^-7 N

Question 13

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

Accepted Answer

1.6 cm

Answer

2.5cm

Answer

5cm

Answer

8.3cm

Question 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? (me=9.11*10-31) ?

Accepted Answer

59.2*$$10^6m$$/s

Answer

2.7*$$10^6m$$/s

Answer

17.5*$$10^6m$$/s

Answer

29.6*$$10^6m$$/s

Question 15

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

Accepted Answer

0.9m from q1

Answer

0.9m from q2

Answer

1m from q1

Answer

0.4 from q1

Question 16

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

Accepted Answer

-2.9*10^-7 V

Answer

-2.2*10^-9 V

Answer

3.0*10^-7 V

Answer

3.6*$$10^9$$ V

Question 17

In the figure, what is the net force on q2 if q1=80&micro;C, q2= -200&micro;C and q3= 60&micro;C?

Accepted Answer

31.4N

Answer

21.2N

Answer

9.7N

Answer

15.7N

Question 18

A parallel &ndash;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 ?

Accepted Answer

8.85PC

Answer

0.8C

Answer

45nC

Answer

22nC

Question 19

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

Accepted Answer

-2.64*$$10^5$$ V

Answer

1.3*$$10^3$$ V

Answer

-1.3*$$10^3$$ V

Answer

2.64*$$10^5$$ V

Question 20

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

Accepted Answer

C=1/2Co

Answer

C=Co

Answer

C=2Co

Answer

C=3/2Co

Physics 103 Exam

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

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?

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

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 :

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?

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?

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 ?

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 ?

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⁾

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?

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

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 ?

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

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) ?

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 ?

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

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

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 ?

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)?

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