Physics Chapter 1-Conceptual Question Test 1

Newton's law of universal gravitation is represented by F =(G)Mmr/2 where F is the gravitational force, M and m are masses, and r is a length. Force has the SI units kg(m/s^2). What are the SI units of the proportionality constant G?

(m^3)/kg · s2

A house is advertised as having 1420 square feet under roof. What is the area of this house in square meters?

132

0.0056

2 sig figs

2.6 ✕ 10−6

2 sig figs

81.0 ± 0.5

3 sig figs

4.0850 ✕ 109

5 sig figs

Use the rules for significant figures to find the answer to the addition problem 21.4 + 15 + 17.17 + 4.003.

58

A displacement is related to time as x = A sin(2πft), where A and f are constants. Find the dimensions of A. (Hint: A trigonometric function appearing in an equation must be dimensionless.)

L

Suppose that the displacement of an object is related to time according to the expression x = Bt2. What are the dimensions of B?

L/T^2

If an equation is dimensionally correct, does this mean that the equation must be true?

No

Must two quantities have the same dimensions if you are dividing them?

No

Must two quantities have the same dimensions if you are multiplying them?

No

If an equation is not dimensionally correct, does this mean that the equation can't be true?

Yes

Must two quantities have the same dimensions if you are adding them?

Yes

Must two quantities have the same dimensions if you are equating them?

Yes

Must two quantities have the same dimensions if you are subtracting them?

Yes

Newton's second law of motion says that the mass of an object times its acceleration is equal to the net force on the object. Which of the following gives the correct units for force?

kg · m/s2

Which of the following relationships is dimensionally consistent with an expression yielding a value for acceleration? Acceleration has the units of distance divided by time squared. In these equations, x is a distance, t is time, and v is velocity with units of distance divided by time.

v2/x