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3 years ago

An automobile engine has an efficiency of 22.0% and produces 2510 J of work. How much heat is rejected by the engine

Physics

1 answer:

katrin [286]3 years ago

5 0

Answer:

If efficiency is .22 then W = .22 * Q where Q is the heat input

Heat Input Q = 2510 / .22 = 11,400 J

Heat rejected = 11.400 - 2510 = 8900 J of heat wasted

Also, 8900 J / (4.19 J / cal) = 2120 cal

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2. A truck speeds up from a velocity of 6 m/s to 14 m/s in 4 seconds. What is the trucks acceleration? SHOW YOUR WORK

zavuch27 [327]

As it is given here

initial speed is

$v_i = 6 m/s$

After 4 seconds the final speed is

$v_f = 14 m/s$

so here we can use the formula of acceleration using kinematics

$a = \frac{v_f - v_i}{t}$

$a = \frac{14 - 6}{4}$

$a = 2 m/s^2$

so here it will accelerate at 2 m/s^2 rate.

As it is given here

initial it starts from rest

$v_i = 0 m/s$

After 2.5 seconds the final speed is

$v_f = 15 m/s$

so here we can use the formula of acceleration using kinematics

$a = \frac{v_f - v_i}{t}$

$a = \frac{15 - 0}{2.5}$

$a = 6 m/s^2$

so here it will accelerate at 6 m/s^2 rate.

i think question is not correct as in first line it is saying about a bag of trash and then in next line it is asking for the position of Jumper and bridge.

7 0

2 years ago

If another vehicle is trying to pass your vehicle,

Vladimir [108]

Answer:

Reduce you're speed, and let the other vehicle pass you

8 0

3 years ago

Water is discharged from a pipeline at a velocity v (in ft/sec) given by v = 1306p(1/2), where p is the pressure (in psi). If th

shepuryov [24]

Answer:

$a=38.5 ft/sec^{2}$

Explanation:

Note that acceleration is the rate change of velocity i.e

$acceleration=\frac{change in velocity}{change in time}\\a=\frac{dv}{dt} \\$ .

Since the velocity is giving as a variable dependent on the pressure, we have to differentiate implicitly both side with respect to time,i.e

$\frac{dv}{dt}=1306*(1/2)p^{-1/2}\frac{dp}{dt} \\$

if we substitute value for the pressure as giving in the question and also since the rate change of pressure is 0.354psi/sec, we have

$a=653*0.1667*0.354\\$

$a=\frac{dv}{dt}=653(36)^{-1/2}*0.354\\ a=38.5 ft/sec^{2}$

3 0

3 years ago

An athlete kicks a soccer ball that starts at rest so that it leaves their foot with a speed of 10m/s from the top o f a rectang

kirza4 [7]

Answer:

$a=500m/s^2$

Explanation:

We need only to apply the definition of acceleration, which is:

$a=\frac{v_f-v_i}{t_f-t_i}$

In our case the final velocity is $v_f=10m/s$ , the initial velocity is $v_i=0m/s$ since it departs from rest, the final time is $t_f=0.02s$ and the initial time we are considering is $t_i=0s$

So for our values we have:

$a=\frac{10m/s-0m/s}{0.02s-0s}=500m/s^2$

3 0

3 years ago

If Patricia worked 40 hours this week and her paycheck shows that her gross pay is $ 340 , what is her hourly wage?

GrogVix [38]

For 40 hours, she gets paid $340
Therefore, for 1 hour, she gets paid 340/40=$8.50
Her hourly wage is $8.50

8 0

2 years ago