ipc 4a calculate speed, momentum, acceleration, work, and power in systems such as in the human...

IPC 4aCalculate speed, momentum, acceleration, work, and power in systems such as in the human body, moving

toys, and machines;

On the left side: The formula is given in words

On the right side: The formula is given in symbols

Density = D = mass

volume

m

v

Formula Chart

Gravity

Constants, Symbols and

Units

Formulas

Power =Power = work work = = force x distanceforce x distance time timetime time

Newton’s 2Newton’s 2ndnd Law Law

TRIANGLE METHOD-

D = m/v

M

VD

An object has a density of 10 g/cm3 and a volume of 3 cm3. What is its mass?

XX

An object has a mass of 50 g and a volume of 10 cm3. What is its density?

An object has a mass of 50 g and a density of 5 g/cm3. What is its volume?

Answer: 30g

÷÷

Answer: 5g/cm3

Answer: 10cm3

Student Practice: Scrap Paper

TRIANGLE METHOD

f = ma

f

am

An object has a mass of 5g and an acceleration of 8 kg/s2 . What force does it exert?

XX

An object exerts a force of 100N and has a mass of 50 kg . What is its acceleration?

An object has a force of 200N and an acceleration of 2kg/ s2. What is its mass?

÷÷

Answer: 40N

Answer: 2kg/ s2

Answer: 100 kg

am

f

XX

÷÷

am

f

XX

÷÷

am

Student Practice: Scrap Paper

Triangle Method-Your Turn• Speed = distance/time (v=d/t)

• Power = work/time (p=w/t)

• Velocity of a wave=frequency x wavelength (v=fλ)

• Current = voltage/resistance (I = v/R)

t

d

v t P

w

t

v

f λ

v

I R

Student Practice: Scrap Paper

When solving a problem---• First read the problem carefully and

list what you know and what you are solving for.

• Second identify the formula from the formula chart that includes what you are given.

• Third Using the triangle method, set up the formula. You may have to rearrange the formula to solve for the unknown quantity.

Which formula?• The weight lifter used a force of 980 N to

raise the barbell 2.04 m over her head in 5.21 seconds. Approximately how much work did she do in raising the barbell?

• Approximately how much power did the weight lifter exert lifting the barbell in 5.21 seconds?

• What is the momentum of a 40 kg bike riders moving at 45 km/h?

• What is the mass of a 500.00 mL sample of seawater with a density of 1.025 g/mL?

Work = force x distance

Power = Work/time

Density = mass/volume

Momentum = mass x velocity

Which of the following weightlifters does themost work on a 100-pound barbell when

liftingthe barbell over his or her head?A. A weightlifter who is 5 feet 8 inches tallB. A weightlifter who is 6 feet 0 inches tallC. A weightlifter who is 6 feet 2 inches tallD. A weightlifter who is 6 feet 4 inches tallFrom formula chart

Force

Distance

Which of the following changes would notincrease power? A. A decrease in the time it takes to do

work.B. A decrease in the distance over which a

force is appliedC. An increase in the force appliedD. An increase in the work added

Power = work = force x distance time time

From formula chart

To decrease power then work must decrease or time increase.

To decrease work you must decrease the force or decrease the distance

When solving a problem---• First read the problem carefully and

list what you know and what you are solving for.

• Second identify the formula from the formula chart that includes what you are given.

• Third Using the triangle method, set up the formula. You may have to rearrange the formula to solve for the unknown quantity.

WHAT FORMULA??

• Get out your white board and a dry erase marker

• We will play a game called “What Formula”

• When you are shown the problem, look at your formula chart and select the formula you would use to solve the problem

• Write the formula on your white board and turn it so your teacher can see it. (You DON’T need to solve the problem)

What Formula?

V = d/t

Speed = distance

traveled/time

What Formula?

P=w/t

Power = work/time

What Formula?

KE = mv2/2

Kinetic Energy = ½

(mass x velocity2)

What Formula?

p = m x a

Momentum = mass x

acceleration

What Formula?

V = d/t

Speed = distance

traveled/time

What Formula?

F = m/a

Force = mass/

acceleration

What Formula?a = vf-vi/∆t

Acceleration = final

velocity – initial

velocity/ change in

time

What Formula?

V = d/t

Speed = distance

traveled/time

What Formula?

P=w/t

Power = work/time

What Formula?

F = m/a

Force = mass/

acceleration

What Formula?a = vf-vi/∆t

Acceleration = final

velocity – initial

velocity/ change in

time

What Formula?

V = d/t

Speed = distance

traveled/time

Density Foldable

We will now make a Density

foldable

Density Foldable

DENSITY

FORMULA

UNITS

SAMPLE PROBLEMS & SOLUTIONS

g=g/cm3 x cm3

g/cm3=g/cm3

Cm3=g/g/cm3

m=D x v

D=m/v

V=m/D

Inside Foldable

Definition Under FlapDensity is the amount of mass in a given

volume

D=m/v; v=m/D; m=D x v

FORMULA

UNITS

SAMPLE PROBLEMS

GOOD LUCK!!!!