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3 years ago

A car travels in a straight line for 4.4 h at a constant speed of 81 km/h. What is its acceleration?

Physics

2 answers:

Fed [463]3 years ago

7 0

The speed and length of time don't matter.

Constant speed in a straight line is the DEFINITION of ZERO acceleration.

irga5000 [103]3 years ago

5 0

Answer:

$a = 0m/s^2$

Explanation:

we can use the equation:

$v_f = a(t) + v_i$

And plug in our numbers:

$81km/h = am/s^2(4.4h) + 81hm/h$

$0 = am/s^2(4.4h)$

$0 = am/s^2$

$a = 0m/s^2$

Because the speed was constant, there was no difference between the final and initial velocities, meaning that once you do the math you see there is no acceleration affecting the speed.

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A car is traveling at 24.0 m/s when the driver suddenly applies the brakes, causing the car to slow down with constant accelerat

Elan Coil [88]

Answer:

The answer to your question is : vf = 15.18 m/s

Explanation:

Data

vo = 24 m/s

d = 120 m

vf = ? when d = 60.0 m

Formula

vf² = vo² + 2ad

For d =100m

a = (vf² - vo²) / 2d

a = (0 -24²) / 2(100)

a = -576/200

a = 2.88 m/s²

Now, when d = 60

vf² = (24)² - 2(2.88)(60)

vf² = 576 - 345.6

vf² = 230.4

vf = 15.18 m/s

4 0

3 years ago

Read 2 more answers

Direct tension indicators are sometimes used instead of torque wrenches to ensure that a bolt has a prescribed tension when used

natali 33 [55]

Complete Question

The complete question is shown on the uploaded image

Answer:

The tension on the shank is $T =8391.6 N$

Explanation:

From the question we are told that

The strain on the strain on the head is $\Delta l = 0.1 mm/mm = \frac{0.1}{1000} = 0.1 *10^{-3} m/m$

The contact area is $A = 2.8 mm^2 = 2.8* (\frac{1}{1000} )^2 = 2.8*10^{-6} m^2$

Looking at the first diagram

At 600 MPa of stress

The strain is $0.3mm/mm$

At 450 MPa of stress

The strain is $0.0015 mm/mm$

To find the stress at $\Delta l$ we use the interpolation method

$\frac{\sigma_{\Delta l} - \sigma_{0.0015} }{ \sigma _ {0.3} - \sigma_{0.0015} } = \frac{e_{\Delta l } - e_{0.0015}}{e_{0.3} - e_{ 0.0015}}$

Substituting values

$\frac{\sigma _{\Delta l} - 450}{600 - 450} = \frac{0.1 -0.0015}{0.3 - 0.0015}$

$\sigma _{\Delta l} -450 = 49.50$

$\sigma _{\Delta l} = 499.50 MPa$

Generally the force on each head is mathematically represented as

$F = \sigma_{\Delta l} * A$

Substituting values

$F = 499.50*10^{6} * 2.8*10^{-6}$

$=1398.6N$

Now the tension on the bolt shank is as a result of the force on the 6 head which is mathematically evaluated as

$T = 6 * F$

$= 6* 1398.6$

$T =8391.6 N$

6 0

3 years ago

Watt-hours is a measure of energy, just like kilowatt-hours. How can you convert this to Joules?

satela [25.4K]

Work with your units:

1 watt-hour = 1 (joule/second) · (hour) = 1 (joule-hour / second)

(1 joule-hour/sec) · (3600 sec/hour) = 3600 joules

So 1 watt-hour = 3,600 joules

3 0

2 years ago

A bird flies 10 miles south, turns and flies 15 miles east. What distance did it fly.

vfiekz [6]

Answer:

wouldn't it be 25 miles?? yeah

Explanation:

4 0

2 years ago

If the relative density of a liquid is 0.34 what is the density of the liquid

Elina [12.6K]

Answer:

Explanation:

The formula for calculating the relative density of a substance is expressed as

Relative density of a liquid = Density of the liquid /density of water

Given relative density of a liquid = 0.34

Density of water 997kg/m³

Substituting into the formula we have;

Density of the liquid = Relative density of a liquid * density of water

Density of the liquid = 0.34 * 997

Density of the liquid = 3338.98 kg/m³

7 0

2 years ago