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3 years ago

How much work is done to push a car 20m using a 200 N force?

Physics

1 answer:

Vera_Pavlovna [14]3 years ago

7 0

Answer:

F=200N d=20m t=30s

W=F*d

W=200*20

W=4000J

P=W/t

P=4000/30

P=400/3

P=133.333333334 W

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Determine the angular speed, in rad/s of:

ryzh [129]

Answer:

Explanation:

A. The earth about its axis:

The earth makes one revolution in 24 hours. to know the number of revolutions per second it makes, we need to convert hours to seconds and the revolution to rad.

$\frac{1 rev}{24hours}\times \frac{1 hr}{3600s}\times \frac{2\pi}{1}= 7.27 \times10^-5 rad/s$

B. The minute hand of the clock makes one revolution in 60 minutes

To convert this to rad per second, we have

$\frac{1 rev}{60mins}\times \frac{1 min}{60s}\times \frac{2\pi}{1}= 1.745 \times10^-3rad/s$

C. The hour hand of a clock completes one revolution in 12 hours

$\frac{1 rev}{12hours}\times \frac{1 hr}{3600s}\times \frac{2\pi}{1}= 1.454 \times10^-4 rad/s$

D. an egg beater turning at 300 rpm.

$\frac{300 rev}{1minute}\times \frac{1 min}{60s}\times \frac{2\pi}{1}= 7.27 \times10^-5 rad/s=0.0218rad/s$

6 0

2 years ago

A calorimeter is used to determine the specific heat capacity of a test metal. If the specific heat capacity of water is known,

denis23 [38]

Answer:

initial and final temperatures of both the water and metal, mass of the metal, and mass of the water

Explanation:

Heat lost by the metal, $Q = mc(t_{2} - t_{1})$

Heat gained by the water in the calorimeter, $Q_{w} = m_{w}c_{w}(t_{2w} - t_{1w})$

For energy to be conserved in the system, the heat lost by the metal will equal the heat gain by the water in the calorimeter.

$mc(t_{2} - t_{1}) = m_{w}c_{w}(t_{2w} - t_{1w})$

Where,

m is the mass of the metal

c is specific heat capacity of the metal

t₂ is the final temperature of the metal

t₁ is the initial temperature of the metal

$m_{w}$ is the mass of the water

$c_{w}$ is specific heat capacity of water

$t_{2w}$ is the final temperature of water

$t_{1w}$ is the initial temperature of water

From the question given, specific heat capacity of the water is known, the quantities to be measured are;

Initial and final temperatures of both the water and metal,

Mass of the metal, and mass of the water

8 0

3 years ago

Question 4 of 10

Alexus [3.1K]

Answer:

22.3 kg•m/s

Explanation:

Apex;)

7 0

3 years ago

A football quarterback runs 15.0 m straight down the playing field in 3.00 s. He is then hit and pushed 3.00 m straight backward

algol [13]

Answer:

a) $v_{1}=14.29m/s\\v_{2}=9.25m/s\\v_{3}=6.36m/s$

b) $v=+9.97m/s$

Explanation:

From the exercise we know that

$x_{1} =15m, t_{1}=3s$

$x_{2} =-3m, t_{1}=1.74s$

$x_{3} =29m, t_{3}=5.20s$

From dynamics we know that the formula for average velocity is:

$v=\frac{x_{2}-x_{1} }{t_{2}-x_{1} }$

a) For the three intervals:

$v_{1}=\frac{x_{2}-x_{1} }{t_{2}-t_{1} }=\frac{(-3-15)m}{(1.74-3)s}=14.29m/s$

$v_{2}=\frac{x_{3}-x_{2} }{t_{3}-t_{2} }=\frac{(29-(-3))m}{(5.20-1.74)s}=9.25m/s$

$v_{3}=\frac{x_{3}-x_{1} }{t_{3}-t_{1} }=\frac{(29-15)m}{(5.20-3)s}=6.36m/s$

b) The average velocity for the entire motion can be calculate by the following formula:

$v=\frac{v_{1}+v_{2}+v_{3} }{n} =\frac{(14.29+9.25+6.36)m/s}{3}=+9.97m/s$

8 0

3 years ago

The large blade of a helicopter is rotating in a horizontal circle. The length of the blade is 7.26 m, measured from its tip to

Elan Coil [88]

Answer:

$\frac{a_1}{a_2}=1.67$

Explanation:

The equation for centripetal acceleration is $a_{cp}=r\omega^2$ . If $r_1=7.26m$ is the distance from the center of the point at the tip of the blade and $r_2=4.35m$ is the distance from the center of another point in the blade, and since both points are rotating at the same angular velocity $\omega$ because both of them belong to the blade, the ratio between their centripetal accelerations will be:

$\frac{a_1}{a_2}=\frac{r_1 \omega^2}{r_2 \omega^2}=\frac{7.26m}{4.35m}=1.67$

5 0

3 years ago