Q: A 50 kg parachutist descends at a steady 40.1 m/s. What is the drag force acting on the parachutist?

$$F_{\text{drag}} = 490 \, \mathrm{N}$$

Q: At what altitude above Earth's surface must a satellite complete a circular orbit in 2.0 hours? (Given $$M_E = 5.97 \times 10$$^{24}$$ \, \mathrm{kg}$$, $$R_E = 6.37 \times 10^6$ \, \mathrm{m}$$, $$G = 6.67 \times 10$$^{-11}$$ \, \mathrm{N\,m^2$/kg^2$$}$)

$$h = 1.68 \times 10^6$ \, \mathrm{m}$$

Q: What is the angular speed in rad/s of the Earth about its axis? (Earth's period $$T = 24 \times 60 \times 60 s)$$

$$\omega = 7.3 \times 10$$^{-5}$$ \, \mathrm{rad/s}$$

Question 1

A rock is dropped into a well and you hear the splash 4.4 seconds later. Ignoring the time for sound to travel back up, how deep is the well? (Take $$g = 9.8 \, \mathrm{m/s^2$})$$

Accepted Answer

$$h = 95 \, \mathrm{m}$$

Question 2

You walk 222 m east, then 150 m south. What is the magnitude of your displacement vector?

Accepted Answer

$$\Delta x = 266 \mathrm{\ m}$$

Question 3

A 50 kg parachutist descends at a steady 40.1 m/s. What is the drag force acting on the parachutist?

Accepted Answer

$$F_{	ext{drag}} = 490 \, \mathrm{N}$$

Question 4

A 14.6 kg monkey hangs from the middle of a massless rope, each half of which makes a $$20^\circ$$ angle with the horizontal. What is the tension in the rope?

Accepted Answer

$$T = 72.9 \, \mathrm{N}$$

Question 5

A sprinter completes a 100 m dash in 10.6 s, doing $$22.4 	imes 10^3$ J of work. What is the power output?

Accepted Answer

$$P = 2.11 \mathrm{\ kW}$$

Question 6

At what altitude above Earth's surface must a satellite complete a circular orbit in 2.0 hours? (Given $$M_E = 5.97 	imes 10$$^{24}$$ \, \mathrm{kg}$$, $$R_E = 6.37 	imes 10^6$ \, \mathrm{m}$$, $$G = 6.67 	imes 10$$^{-11}$$ \, \mathrm{N\,m^2$/kg^2$$}$)

Accepted Answer

$$h = 1.68 	imes 10^6$ \, \mathrm{m}$$

Question 7

Two masses, $$m_1 = 9$ kg and m_2$ = 4 kg$$, collide elastically. If $$m_1 is $$initially at rest and $$m_2$$ moves at $$0.6 \, \mathrm{m/s}$$, what is the velocity of $$m_2$$ after the collision?

Accepted Answer

$$v_2 = 0.47$$ \, \mathrm{m/s}$$, opposite to m_1$'s initial direction

Question 8

What is the angular speed in rad/s of the Earth about its axis? (Earth's period $$T = 24 	imes 60 	imes 60 s)$$

Accepted Answer

$$\omega = 7.3 	imes 10$$^{-5}$$ \, \mathrm{rad/s}$$

Question 9

A wheel of diameter 62 cm rotates at 700 rpm. What is its angular velocity in rad/s?

Accepted Answer

$$\omega = 63 \, \mathrm{rad/s}$$

Question 10

A block of mass $$1.055 kg $$and volume $$4.8 	imes 10$$^{-4}$$ \, \mathrm{m^3$} is $$placed in water. What is the normal force from the bottom if it sinks? ($$g = 9.8 \, \mathrm{m/s^2$}$$, $$ho_{	ext{water}} = 1000 \, \mathrm{kg/m^3$})$$

Accepted Answer

$$F_N = 10.334 \, \mathrm{N}$$

Question 11

Given two identical strings, String A has a period of 6 s and String B has a period of 2 s. What is the ratio of their frequencies $$f_A / f_B$$?

Accepted Answer

$$f_A / f_B = 1/3$$

Question 12

If the energy of a wave is directly proportional to its frequency, and String A has a frequency of $$0.17 \, \mathrm{Hz}$$ while String B has $$0.5 \, \mathrm{Hz}$$, what is the ratio of their energies $$E_A / E_B$$?

Accepted Answer

$$E_A / E_B = 1/3$$

Question 13

A 120 W speaker emits sound waves isotropically. What is the intensity at a distance of 1 m from the speaker?

Accepted Answer

$$I = 9.5 \, \mathrm{W/m^2$}$$

Question 14

What is the sound level in decibels at 1 m from a 120 W speaker? ($$I_0 = 1.0$$ 	imes $$10^{-12}$$ \, \mathrm{$$W/m^2$$}$$)

Accepted Answer

$$\beta = 130 \, \mathrm{dB}$$

Question 15

A block of mass $$1.055 kg $$and density $$2198 \, \mathrm{kg/m^3$} is $$placed in water. Will it float or sink?

Accepted Answer

It will sink.

Question 16

A satellite orbits Earth at a radius $$r. $$What is the expression for its orbital speed $$v$$?

Accepted Answer

$$v = \sqrt{\dfrac{GM_E}{r}}$$

Question 17

A 0.31 m radius wheel spins at 700 rpm. What is the linear speed at the rim?

Accepted Answer

$$v = 19.4 \, \mathrm{m/s}$$

Comprehensive Study Notes for PHY250 Physics I Final Exam Topics

스터디 가이드 - 연습 문제

학습 가이드 - 플래시카드