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3 years ago

a runner covers the last straigjt stretch of a race in 4 s. during that time, he speeds up from 5m/s to 9m/s.

1 answer:

8 0

During that final period of time,
his acceleration is
(9 m/s - 5 m/s) / (4 sec) = 1 m/s² .

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Two protons are released from rest when they are 0.750 {\rm nm} apart.

Alex787 [66]

Explanation:

Given:

m = 1.673 × 10^-27 kg

Q = q = 1.602 × 10^-19 C

r = 0.75 nm

= 0.75 × 10^-9 m

Energy, U = (kQq)/r

Ut = 1/2 mv^2 + 1/2 mv^2

1.673 × 10^-27 × v^2 = (8.99 × 10^9 × (1.602 × 10^-19)^2)/0.75 × 10^-9

v = 1.356 × 10^4 m/s

F = (kQq)/r^2

F = m × a

1.673 × 10^-27 × a = ((8.99 × 10^9 × (1.602 × 10-19)^2)/(0.075 × 10^-9)^2

a = 2.45 × 10^17 m/s^2.

4 0

3 years ago

What volume (in liters) of gasoline has a total heat of combustion equal to the energy obtained in part (a)? (see section 17.6;

antiseptic1488 [7]

<h3><u>Answer;</u></h3>

volume = 6.3 × 10^-2 L

<h3><u>Explanation</u>;</h3>

Volume = mass/density

Mass = 0.0565 Kg,

Density = 900 kg/m³

= 0.0565 kg/ 900 kg /m³

= 6.3 × 10^-5 M³

but; 1000 L = 1 m³

Hence, <u>volume = 6.3 × 10^-2 L</u>

8 0

3 years ago

Please help!

julsineya [31]

Answer:

Answer:

3 g/cm

Explanation:

Mass of stone = 30 g

Initial volume of cylinder = 50 cm

Increased volume = 60 cm

Volume = 60-50

= 10 cm

Density of stone = Mass/Volume

= 30/10

= 3 g/ml as 1 ml = 1 cm

= 3 g/ml

Explanation:

6 0

3 years ago

an object is placed 20cm from a converging lens. If the real image is formed 80cm from the object, what is the focal length of t

masya89 [10]

Explanation:

Here,

object distance(u)=20cm

image distance(v)=80cm-20cm=60cm

focal length(f)=?

we know ,

(1/f)=(1/v)+(1/u)

1/f = 1/60 + 1/20

1/f = (1+3)/60

60 =4f

f=15cm

8 0

2 years ago

While taking off from an aircraft carrier, a jet starting from rest accelerates uniformly to a final speed of 40. meters per sec

mariarad [96]

The acceleration of the jet is $11.4 m/s^2$

Explanation:

Since the jet motion is a uniformly accelerated motion (=constant acceleration), we can use the following suvat equation:

$v^2-u^2=2as$

where

v is the final velocity

u is the initial velocity

a is the acceleration

s is the displacement

For the jet in this problem, we have

u = 0 (it starts from rest)

v = 40 m/s (final velocity)

s = 70 m (length of the runway)

Solving for a, we find the acceleration:

$a=\frac{v-u}{t}=\frac{40^2-0}{2(70)}=11.4 m/s^2$

Learn more about acceleration:

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#LearnwithBrainly

5 0

3 years ago