Q: A projectile is launched horizontally from a $$45\ \mathrm{m}$$ high cliff with an initial speed of $$10\ \mathrm{m/s}. $$How far from the base of the cliff does it land? (Assume $$g = 9.8\ \mathrm{m/s^2$})$$

$$10\ \mathrm{m/s} \times \sqrt{\dfrac{2 \times 45}{9.8}} = 30.3\ \mathrm{m}$$

Q: A $$3\ \mathrm{kg}$$ block slides down a frictionless incline of height $$5\ \mathrm{m}. $$What is its speed at the bottom?

$$\sqrt{2gh} = \sqrt{2 \times 9.8 \times 5} = 9.9\ \mathrm{m/s}$$

Q: A $$2\ \mathrm{kg}$$ block is attached to a string and spun in a vertical circle of radius $$1\ \mathrm{m}. $$What is the minimum speed at the top of the circle to keep the string taut? ($$g = 9.8\ \mathrm{m/s^2$})$$

$$\sqrt{g r} = \sqrt{9.8 \times 1} = 3.13\ \mathrm{m/s}$$

Q: A $$1.2\ \mathrm{kg}$$ block is floating in water. What is the buoyant force acting on the block?

$$1.2 \times 9.8 = 11.76\ \mathrm{N}$$

Q: A standing wave is formed on a string fixed at both ends. If the string is $$1.5\ \mathrm{m}$$ long and the wave speed is $$60\ \mathrm{m/s}$$, what is the frequency of the second harmonic?

$$f_2$$ = \dfrac{2v}{2L} = \dfrac{2 \times 60}{2 \times 1.5} = 40\ \mathrm{Hz}$$

Q: A $$0.3\ \mathrm{kg}$$ mass is attached to a spring and oscillates with a period of $$0.5\ \mathrm{s}. $$What is the spring constant $$k$$?

$$k = \dfrac{4\pi^2$ m}{T^2$} = \dfrac{4 \times \pi^2$ \times 0.3}{0.25} = 47.4\ \mathrm{N/m}$$

Question 1

A car accelerates uniformly from rest to a velocity of $$20\ \mathrm{m/s} in$$ $$5\ \mathrm{s}. $$What is the magnitude of its acceleration?

Accepted Answer

$$2\ \mathrm{m/s^2$}$$

Question 2

A student measures the length of a table three times and records $$2.00\ \mathrm{m}$$, $$2.01\ \mathrm{m}$$, and $$1.99\ \mathrm{m}. $$What is the best estimate of the table's length and its uncertainty?

Accepted Answer

$$2.00 \pm 0.01\ \mathrm{m}$$

Question 3

A projectile is launched horizontally from a $$45\ \mathrm{m}$$ high cliff with an initial speed of $$10\ \mathrm{m/s}. $$How far from the base of the cliff does it land? (Assume $$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$10\ \mathrm{m/s} 	imes \sqrt{\dfrac{2 	imes 45}{9.8}} = 30.3\ \mathrm{m}$$

Question 4

Which of the following best describes Newton's Third Law of Motion?

Accepted Answer

For every action, there is an equal and opposite reaction.

Question 5

A $$5\ \mathrm{kg}$$ block is pulled across a horizontal surface with a force of $$30\ \mathrm{N}. If $$the coefficient of kinetic friction is $$0.2$$, what is the acceleration of the block? ($$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$3.2\ \mathrm{m/s^2$}$$

Question 6

A ball of mass $$0.5\ \mathrm{kg}$$ moving at $$4\ \mathrm{m/s}$$ collides elastically with a stationary ball of mass $$0.5\ \mathrm{kg}. $$What is the velocity of the first ball after the collision?

Accepted Answer

$$0\ \mathrm{m/s} ($$the first ball stops and the second moves at $$4\ \mathrm{m/s})$$

Question 7

A $$2\ \mathrm{kg}$$ object is attached to a spring with a force constant $$k = 50\ \mathrm{N/m}. $$What is the period of oscillation for this mass-spring system?

Accepted Answer

$$2\pi \sqrt{\dfrac{2}{50}} = 1.26\ \mathrm{s}$$

Question 8

A $$1.5\ \mathrm{kg}$$ object is moving in a circle of radius $$2\ \mathrm{m} at a $$constant speed of $$3\ \mathrm{m/s}. $$What is the magnitude of the centripetal force acting on the object?

Accepted Answer

$$6.75\ \mathrm{N}$$

Question 9

A $$0.2\ \mathrm{kg}$$ ball is dropped from a height of $$10\ \mathrm{m}. $$What is its velocity just before hitting the ground? (Neglect air resistance, $$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$14\ \mathrm{m/s}$$

Question 10

A $$3\ \mathrm{kg}$$ block slides down a frictionless incline of height $$5\ \mathrm{m}. $$What is its speed at the bottom?

Accepted Answer

$$\sqrt{2gh} = \sqrt{2 	imes 9.8 	imes 5} = 9.9\ \mathrm{m/s}$$

Question 11

A $$0.5\ \mathrm{kg}$$ object moving at $$6\ \mathrm{m/s}$$ collides inelastically with a $$1.0\ \mathrm{kg}$$ object at rest. What is their final velocity after the collision?

Accepted Answer

$$2\ \mathrm{m/s}$$

Question 12

A $$10\ \mathrm{kg}$$ box is at rest on a horizontal surface. The coefficient of static friction is $$0.4. $$What is the minimum force required to start moving the box? ($$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$39.2\ \mathrm{N}$$

Question 13

A $$0.1\ \mathrm{kg}$$ mass is attached to a string and swung in a horizontal circle of radius $$0.5\ \mathrm{m} at$$ $$2\ \mathrm{m/s}. $$What is the tension in the string?

Accepted Answer

$$0.8\ \mathrm{N}$$

Question 14

A $$2\ \mathrm{kg}$$ block is attached to a string and spun in a vertical circle of radius $$1\ \mathrm{m}. $$What is the minimum speed at the top of the circle to keep the string taut? ($$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$\sqrt{g r} = \sqrt{9.8 	imes 1} = 3.13\ \mathrm{m/s}$$

Question 15

A $$0.5\ \mathrm{kg}$$ object is heated from $$20^\circ\mathrm{C} to$$ $$70^\circ\mathrm{C}$$, absorbing $$10,500\ \mathrm{J} of $$heat. What is the specific heat capacity of the object?

Accepted Answer

$$420\ \mathrm{J/(kg\cdot ^\circ C)}$$

Question 16

A $$1.2\ \mathrm{kg}$$ block is floating in water. What is the buoyant force acting on the block?

Accepted Answer

$$1.2 	imes 9.8 = 11.76\ \mathrm{N}$$

Question 17

A standing wave is formed on a string fixed at both ends. If the string is $$1.5\ \mathrm{m}$$ long and the wave speed is $$60\ \mathrm{m/s}$$, what is the frequency of the second harmonic?

Accepted Answer

$$f_2$$ = \dfrac{2v}{2L} = \dfrac{2 	imes 60}{2 	imes 1.5} = 40\ \mathrm{Hz}$$

Question 18

A $$0.3\ \mathrm{kg}$$ mass is attached to a spring and oscillates with a period of $$0.5\ \mathrm{s}. $$What is the spring constant $$k$$?

Accepted Answer

$$k = \dfrac{4\pi^2$ m}{T^2$} = \dfrac{4 	imes \pi^2$ 	imes 0.3}{0.25} = 47.4\ \mathrm{N/m}$$

Question 19

A $$2\ \mathrm{kg}$$ object at $$100^\circ\mathrm{C} is $$placed in $$4\ \mathrm{kg} of $$water at $$20^\circ\mathrm{C}. If $$the final temperature is $$30^\circ\mathrm{C}$$, what is the specific heat capacity of the object? (Assume $$c_{water} = 4200\ \mathrm{J/(kg\cdot ^\circ C)}$$ and no heat loss to the environment.)

Accepted Answer

$$c = \dfrac{4 	imes 4200 	imes (30-20)}{2 	imes (100-30)} = 267\ \mathrm{J/(kg\cdot ^\circ C)}$$

College Physics I Lab Syllabus and Study Guide

스터디 가이드 - 연습 문제

학습 가이드 - 플래시카드