Question 1

A pipe delivers water at the rate of 95 gal/min. What is the rate in $$\mathrm{ft^3$/s}$$? (Given: $$1\ \mathrm{gal} = 231\ \mathrm{in^3$}$$, $$1\ \mathrm{ft} = 12\ \mathrm{in}$$, $$1\ \mathrm{min} = 60\ \mathrm{s})$$

Accepted Answer

$$2.04\ \mathrm{ft^3$/s}$$

Question 2

A car travels at a constant speed of 65 miles per hour. What is this speed in $$\mathrm{m/s}$$? (Given: $$1\ \mathrm{mile} = 5280\ \mathrm{ft}$$, $$1\ \mathrm{ft} = 0.3048\ \mathrm{m}$$, $$1\ \mathrm{hr} = 3600\ \mathrm{s})$$

Accepted Answer

$$29.0\ \mathrm{m/s}$$

Question 3

A person swings a bat and hits a heavy box with a force of $$1500\ \mathrm{N}. $$What is the force the box exerts on the bat?

Accepted Answer

Exactly $$1500\ \mathrm{N}$$, regardless of whether the box moves

Question 4

Two objects are thrown from the top of a tall building, one up and one down, both with the same initial speed. Neglecting air resistance, what are their speeds when they hit the street?

Accepted Answer

They are traveling at the same speed

Question 5

A $$5.0\ \mathrm{kg}$$ box is pulled simultaneously by a $$10.0\ \mathrm{N}$$ force and a $$5.0\ \mathrm{N}$$ force in the same direction. What is the resulting acceleration of the box?

Accepted Answer

$$2.0\ \mathrm{m/s^2$}$$

Question 6

A medicine ball is tossed to you while you are standing on a skateboard. Which action will maximize the speed at which you move after contacting the ball?

Accepted Answer

Push the ball away from you

Question 7

A child standing on a bridge throws a rock straight down. The rock leaves the child's hand at $$t=0. $$Which graph best represents the velocity of the stone as a function of time?

Accepted Answer

A straight line with positive slope starting above zero

Question 8

A person in an elevator is traveling upward but is gradually slowing down at a rate of $$9\ \mathrm{m/s^2$}. If$$ $$F_N is $$the force of the floor on the person and $$F_g is $$the force of gravity on the person, which is true?

Accepted Answer

$$F_N \u003c F_g$$

Question 9

A brick slides down an incline at constant velocity. The frictional force acting on the brick, along the incline, is:

Accepted Answer

Equal to the component of the weight parallel to the incline

Question 10

For general projectile motion, when the projectile is at the highest point of its trajectory:

Accepted Answer

Its velocity is perpendicular to the acceleration

Question 11

A woodpecker's head has a mass of $$9.0\ \mathrm{g}$$ and accelerates at $$3000\ \mathrm{m/s^2$}$$ when striking a tree. What is the magnitude of the force on the woodpecker's head?

Accepted Answer

$$27\ \mathrm{N}$$

Question 12

You are driving home from the grocery store at $$17\ \mathrm{m/s}$$ with a $$7.0\ \mathrm{kg}$$ bag of groceries on the front seat when the light ahead turns red. What is the shortest distance in which you can stop, after the brakes are applied, without the groceries sliding off the seat? (Static friction coefficient $$\mu_s = 0.65$$, kinetic $$\mu_k = 0.45$$, $$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$22.2\ \mathrm{m}$$

Question 13

A block of mass $$m is $$pulled by a constant force $$F$$ for $$10\ \mathrm{s} on a $$frictionless surface. What is the speed of the block after $$10\ \mathrm{s}$$?

Accepted Answer

$$v = \dfrac{F}{m} 	imes 10$$

Question 14

A velocity-time graph for a car and a truck shows the car moving at constant velocity and the truck accelerating from rest. At time $$t$$, which is true about the distance traveled by the two vehicles?

Accepted Answer

The car will have traveled further than the truck

Question 15

A person walks at $$1.2\ \mathrm{m/s}$$ toward a building that is $$22\ \mathrm{m}$$ away. At the same time, a balloon is dropped from a height of $$22\ \mathrm{m}. $$Neglecting air resistance, how far from the entrance should the person be when the balloon is let go to arrive at the entrance at the same time as the balloon?

Accepted Answer

$$10.6\ \mathrm{m}$$

Question 16

Which of the following best describes the acceleration of a projectile at the highest point of its trajectory?

Accepted Answer

Equal to $$g$$ downward

Question 17

A block of unknown mass is pulled by a $$20\ \mathrm{N}$$ force and accelerates at $$4\ \mathrm{m/s^2$}. $$What is the mass of the block?

Accepted Answer

$$5\ \mathrm{kg}$$

Question 18

A velocity vector points to the right and an acceleration vector points to the left. What is happening to the object's speed?

Accepted Answer

The object is slowing down

Question 19

A $$0.9\ \mathrm{g}$$ woodpecker's head accelerates at $$3000\ \mathrm{m/s^2$}$$ when striking a tree. What is the magnitude of the force on the head?

Accepted Answer

$$27\ \mathrm{N}$$

Fundamental Concepts and Problem-Solving in Introductory Physics

Guida di studio - Domande di pratica

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