Physics, 07.07.2019 14:30 saharaapollonio

To maintain a constant speed, the force provided by a car’s engine must equal the drag force plus the force of friction of the road (the rolling resistance). what are the drag forces at 50 km/h and 80 km/h for a toyota camry? (drag area is 0.67 m2.)

Answers: 1

Show answers

Answers

Given:
A = 0.67 m², the area perpendicular to the direction of motion
v = 50 km/h and 80 km/h, traveling speeds

The drag force is
F = (1/2) CρAv²
where
C = 0.4, the drag coefficient (a low number for efficiently designed Camry)
ρ = 1.225 kg/m³, density of air

Note that 1 km/h ≈ 0.2778 m/s.
Therefore,
50 km/h = 13.89 m/s
80 km/h = 22.224 m/s

At 50 km/h, the drag force is
F₅₀ = 0.5*0.4*(1.225 kg/m³)*(0.67 m²)*(13.89 m/s)² = 31.67 N
At 80 km/h, the drag force is
F₈₀ = 0.5*0.4*1.225*0.67*22.224² = 81.075 N

Answers:
31.7 N at 50 km/h
81.1 N at 80 km/h

Answer from: Quest

a coal burning power plant

Answer from: Quest

force is based upon mass and acceleration.the statement is not always true.

it can be explained from newton's second law of motion.

as per newton's second law of motion the rate of change of momentum is directly proportional to the applied force and takes place along the direction of force.

mathematically it can be written as -

$f\alpha \frac{dp}{dt}$

⇒ $f= k \frac{dp}{dt}$

here k is the proportionality constant whose value is 1.

$f=\frac{dp}{dt}$

$f= \frac{d[mv]}{dt}$

$f= m\frac{dv}{dt} +v\frac{dm}{dt}$

$f=ma+v\frac{dm}{dt}$ [a is the acceleration=dv/dt]

hence we see that force not only depends on mass and acceleration but also on velocity and rate of change of mass. force f will depend on mass and acceleration only when mass is constant.

hence the statement that force is based upon mass and acceleration is false.

Another question on Physics

Physics, 22.06.2019 01:00

An object is 10. cm from the mirror, its height is 3.0 cm, and the focal length is 2.0 cm. what is the image height? (indicate the object orientation by including the + or - sign with the answer.) hi = cm +1.33 -1.33 +0.75 -0.75

Answers: 2

Answer

Physics, 22.06.2019 09:30

Gasoline comes from petroleum, which is made from ancient living things. petroleum, therefore, contains a type of energy. a. heat b. nuclear c. biological d. chemical potential

Answers: 2

Answer

Physics, 22.06.2019 11:00

Arowboat passenger uses an oar to push the boat off the dock by exerting a force of 40n for 3.0s. what impulse acts on the boat.

Answers: 1

Answer

Physics, 22.06.2019 17:00

In the future, people will only enjoy one sport: electrodisc. in this sport, you gain points when you cause metallic discs hovering on a field to exchange charge. you are an electrodisc player playing the popular four disc variant. the disks have charges of qa = −8.0 µc, qb = −2.0 µc, qc = +5.0 µc, and qd = +12.0 µc. (1) you bring two disks together and then separate them. you measure the resulting charge of these two disks and find that it is +5.0 µc per disk. which two disks did you bring together? (a) a and b (b) a and c (c)a and d (d)b and c(e) b and d (f) c and d. (2) you bring three disks together and then separate them. you measure the resulting charge of these three disks and find that it is +3.0 µc per disk. which three disks did you bring together? a, b, and c (a) a, b, and d (c) a, c, and d (d) b, c, and d. (3) given the resulting charge of each disk measured in (b) is +3.0 µc, how many electrons would you need to add to a disk of this charge to electrically neutralize it? electrons

Answers: 3

Answer

You know the right answer?

To maintain a constant speed, the force provided by a car’s engine must equal the drag force plus th...

Questions