1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
mixer [17]
4 years ago
13

A car accelerates uniformly from rest to 20 m/sec in 5.6 sec along a level stretch of road. Ignoring friction, determine the ave

rage power required to accelerate the car if (a) the weight of the car is 9,000 N, and (b) the weight of the car is 14,000 N.
Physics
1 answer:
bonufazy [111]4 years ago
3 0

Answer:

(a) P=33000W

(b) P=51000W

Explanation:

The average power is defined as the amount of work done during a time interval:

P=\frac{W}{t}(1)

According to work-energy theorem, the work done is equal to the change in kinetic energy. So, we have:

W=\Delta K\\W=K_f-K_0\\W=\frac{mv_f^2}{2}-\frac{mv_0^2}{2}\\(2)

Recall that the weight is given by:

w=mg\\m=\frac{w}{g}(3)

The car accelerates uniformly from rest (v_0=0). Replacing (3) in (2), we have:

W=\frac{wv_f^2}{2g}

(a) Finally, we replace this in (1):

P=\frac{wv_f^2}{2gt}\\P=\frac{9000N(20\frac{m}{s})^2}{2(9.8\frac{m}{s^2})(5.6s)}\\P=33000W

(b)

P=\frac{14000N(20\frac{m}{s})^2}{2(9.8\frac{m}{s^2})(5.6s)}\\P=51000W

You might be interested in
WILL GIVE BRAINLIEST!!!!!!!!!!!!!!!
jek_recluse [69]

Answer:

Ne

Explanation:

Outer shell is complete.

8 0
3 years ago
Define A Gamma Ray .....---_---__☘️​
MrRa [10]

Answer:

gamma ray, or gamma radiation (symbol γ or {\displaystyle \gamma } \gamma ), is a penetrating form of electromagnetic radiation arising from the radioactive decay of atomic nuclei. It consists of the shortest wavelength electromagnetic waves and so imparts the highest photon energy. Paul Villard, a French chemist and physicist, discovered gamma radiation in 1900 while studying radiation emitted by radium. In 1903, Ernest Rutherford named this radiation gamma rays based on their relatively strong penetration of matter; in 1900 he had already named two less penetrating types of decay radiation (discovered by Henri Becquerel) alpha rays and beta rays in ascending order of penetrating power.

6 0
3 years ago
Estimate the number of photons emitted per second from 1.0 cm2 of a person's skin if a typical emitted photon has a wavelength o
Diano4ka-milaya [45]

Answer:

2.63 x 10^18

Explanation:

A = 1 cm^2 = 1 x 10^-4 m^2

λ = 10,000 nm = 10,000 x 10^-9 m = 10^-5 m

T = 37 degree C = 37 + 273 = 310 k

Energy of each photon = h c / λ

where, h is the Plank's constant and c be the velocity of light

Energy of each photon = (6.63 x 10^-34 x 3 x 10^8) / 10^-5 = 1.989 x 10^-20 J

Energy radiated per unit time = σ A T^4

Where, σ is Stefan's constant

Energy radiated per unit time = 5.67 x 10^-8 x 10^-4 x 310^4 = 0.05236 J

Number of photons per second = Energy radiated per unit time / Energy of  

                                                                                               each photon

Number of photons per second = 0.05236 / (1.989 x 10^-20) = 2.63 x 10^18

4 0
3 years ago
50 POINTS HELP ME PLEASE!!!!!!!!!!!!
Mariana [72]

Answer:

W and X

Explanation:

When escaping a rip current, one should always walk to the side until you escape from the rip current. If you walk towards the shore, you have the ability to keep getting dragged toward the current, such as with X and Y.

4 0
4 years ago
Read 2 more answers
Plsss help me!!!!!!!!!
natali 33 [55]
It should be the B
Low frequency and long wavelength
6 0
3 years ago
Other questions:
  • (this is somehow part of my science unit, dont ask why)
    15·1 answer
  • A block and a ball have the same mass and move with the same initial velocity across a floor and then encounter identical ramps.
    15·1 answer
  • When an ice cube sits out on a warm day and melts where does the heat go?
    12·2 answers
  • Newton's First Law of Motion states that an object will remain at rest or in uniform motion in a straight line unless acted upon
    13·1 answer
  • At some instant, a particle traveling in a horizontal circular path of radius 7.90 m has a total acceleration with a magnitude o
    9·1 answer
  • A suspicious-looking man runs as fast as he can along a moving sidewalk from one end to the other, taking 2.90 s. Then security
    10·1 answer
  • Tính số phần trăm phân tử khí trong trọng trường của Trái Đất, có thế năng ep, lớn hơn động năng trung bình chuyển động tịnh tiế
    8·1 answer
  • A quasar is a distant celestial body in space. Investigators use a special telescope and determine that a certain quasar was giv
    7·1 answer
  • Suppose kinetic energy is 4 joules of a moving object what will happen if we increase the speed twice
    8·1 answer
  • .................................
    14·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!