An electron (m = 9.1 × 10?31 kg, q = ?1.6 × 10?19 C) starts from rest at point A and has a speed of 5.0 × 106 m/s at point B. Only electric forces act on it during this motion. Determine the electric potential difference VA?VB.

A. ?71 V
B. +71 V
C. ?26 V
D. +26 V
E. ?140 V


Answer: A

Physics & Space Science

You might also like to view...

In a heat exchanger, as shown in accompanying figure, air flows over brass tubes of 1.8- cm-ID and 2.1-cm-OD that contain steam. The convection heat-transfer coefficients on the air and steam sides of the tubes are 70 W/(m2 K) and 210 W/(m2 K), respectively. Calculate the overall heat transfer coefficient for the heat exchanger (a) based on the inner tube area, (b) based on the outer tube area.

GIVEN
• Air flow over brass tubes containing steam
• Tube diameters
? Inside (Di) = 1.8 cm = 0.018 m
? Outside (Do) = 2.1 cm = 0.021 m
• Convective heat transfer coefficients
? Air side h c= 70 W/(m2 K)
? Steam side h i= 210 W/(m2 K)
FIND
• The overall heat transfer coefficient for the heat exchanger based on
(a) the inner tube area (Ui) and
(b) the outer tube area (Uo)
ASSUMPTIONS
• The heat transfer coefficients are uniform over the transfer surfaces
SKETCH

PROPERTIES AND CONSTANTS
the thermal conductivity of brass at 20°C (kb) = 111 W/(m K)

Physics & Space Science

When Earth was young, its atmosphere had no free ____

a. nitrogen b. oxygen c. helium d. carbon dioxide e. water vapor

Physics & Space Science

One astronomical unit, or one AU is defined as the

What will be an ideal response?

Physics & Space Science

The current supplied by a battery as a function of time is I(t) = (0.88

A)e-t/(6.0 hr). What is the total number of electrons transported from the positive electrode to the negative electrode from the time the battery is first used until it is essentially dead? (e = 1.60 × 10-19 C) A) 1.2 × 1023 B) 4.4 × 1022 C) 5.3 × 1023 D) 3.3 × 1019

Physics & Space Science