Lv 194 points

# Rob

• ### Materials Question?

A solid circular cylinder is needed as a strut. What is the most lightweight solution required to support a 40 kN load with a factor of safety on yield stress of 2 and a strut length of 10 cm?

1. 6061-T6 Aluminum - 40 ksi yield, 0.0975 lbm/in^3

2. 5-5PH H1025 Stainless Steel - 160 ksi yield, 0.282 lbm/in^3

3. Titanium Ti-6Al-4V - 128 ksi, 0.16 lbm/in^3

4. Inconel 625 Annealed - 70 ksi, 0.305 lbm/in^3

• ### A certain sample carries a current of 4 A when the potential difference is 2 V and a current of 10 A when...?

the potential differences is 4 V. This sample:

A) obeys Ohms law

B) has a resistance of 0.5 ohms at 1 V

C) has a resistance of 2.5 ohms at 2 V

D) has a resistance of 25 ohms at 2 V

E) does not have a resistance

• ### A battery is used to charge a a series combination of two identical capacitors...?

If the potential differences across the battery terminals is V and the total charge Q flows through the battery during the charging process then the charge on the positive plate of each capacitor and the potential difference across each capacitor are:

A) Q/2 and V/2, respectively

B) Q and V, respectively

C) Q/2 and V, respectively

D) Q and V/2, respectively

E) Q and 2V, respectively

• ### At one instant an electron is moving in the positions x direction along the x axis in a region where there is?

a uniform magnetic field in the position z direction. When viewed from a point on the positive z axis, it subsequent motion is:

B) counterclockwise around a circle in the xt plane

C) clockwise around a circle in the xy plane

D) in the positive z direction

E) in the negative z direction

A) J/C

B) V/C

C) J^2/C

D) C/J

E) C^2/J

• ### An electron is moving north in a region where the magnetic field is south.?

The magnetic force exerted on the electron is:

A) zero

B) up

C) down

D) east

E) west

• ### The emf of a battery is equal to its terminal potential difference:?

A) under all conditions

B) only when the battery is being charged

C) only when a large current is in the battery

D) only when there is no current in the battery

E) under no conditions

• ### To make a galvanometer into an ammeter, connect:?

A) a high resistance in parallel

B) a high resistance in series

C) a low resistance in series

D) a low resistance in parallel

E) a source of emf in series