Can a ratio be expressed as a percentage

What is the kinetic energy of a 150 kg bear running at 3 m/s?

OverLord2011 [107]

Explanation:

KE = ½ mv²

KE = ½ (150 kg) (3 m/s)²

KE = 675 J

5 0

3 years ago

A straight railroad track is being built to connect two cities. the measured distance of the track between the two cities is 160

elena55 [62]

Let point A be 0.0 miles (first city)
Let point B be 160.5 miles (first city to second city)
Let point C be 28.5 miles (first city to mail stop)

Take C – A = C [28.5 - 0.0 = 28.5] (This checks the distance between city 1 and Mail stop)

Then Take B – C = Distance from the first city to the second city [160.5 - 28.5 = 132 Miles]

Answer: The Mail stop is 132 miles from the Second City.

7 0

3 years ago

A truck using a rope to tow a 2230-kg car accelerates from rest to 13.0 m/s in a time of 15.0s. How strong must the rope be? μk

Leokris [45]

Answer:

The rope must have a force of 10084,21 N

Explanation

Acceleration calculation

The car acceleration is equal to the acceleration of the truck

ac: car acceleration $\frac{m}{s^{2} }$

at: truck acceleration $\frac{m}{s^{2} }$ )

$ac = at= \frac{vf-vi}{t-ti}$ equation(1)

Known information:

vi = Initial speed = 0, ti = initial time = 0

vf = Final speed = 13 $\frac{m}{s}$ , t = final time =5 s

We replaced the known information in the equation(1):

$ac = at = \frac{13-0}{15-0}$

$ac=ac=\frac{13}{15} \frac{m}{s}$

Dynamic analysis

The forces acting on the car are the following:

Wc: Car weight

N: normal force, road force on the car

Ff: Friction force

T: Force of tension

Car weight calculation:

$Wc=mc*g$

mc = Car mass = 2230kg

g = Gravity acceleration=9.8 $\frac{m}{s^{2} }$

$Wc= 2230*9.8$

$Wc=21854 N$

Normal force calculation:

Newton's first law

$sum Fy= 0$

$N-W=0$

$N=W$

$N=21854 N$

Friction force calculation (Ff):

We have the formula to calculate the friction force:

Ff = μk * N Equation (3)

μk kinetic coefficient of friction

We know that μk = 0.373and N= 21854N ,then:

$Ff=0.373*21854$

$Ff=8151.54 N$

Calculation of the tension force in the rope (T):

Newton's Second law

$sum Fx= mc*ac$

$T-Ff=mc*ac$

$T=2230(\frac{13}{15}) + 8151.54$

T=10084,21 N

Answer: The rope must have a force of 10084,21 N

8 0

3 years ago

List three factors that can pollute water.

eimsori [14]

Answer:

Bacteria and Parasites from Sewage. If sewage is improperly treated it can contaminate water with a variety of bacteria and other parasites.

Industrial Waste. ..

Fertilizer and Lawn Chemicals. ...

Silt and Soil. ...

Humans and Water Pollution Through Detergents. ...

Petrochemicals Contribute to Water Pollution.

Explanation:

8 0

3 years ago

Read 2 more answers

Superman is riding his bicycle. At the base of a hill, he has a specific amount of kinetic energy. Then he coasts up the hill wi

algol13

Answer:

D. Friction and air resistance created heat on his trip up the hill.

Explanation:

Energy transformation from one form to another is not 100% efficient. This is the postulate of the first law of thermodynamics.

Most of the energy transformation is not purely 100%.

When energy is transformed, some are usually wasted.

In this case, in moving from bottom up, Superman produced some heat and encountered air resistance.
To reach the top, he must have overcome the resistance and produce enough heat to power him through.
This reduces the amount of potential energy that should have been the same as the kinetic energy down below.

7 0

3 years ago