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Stop to Think 7.1 Which one is greater- the attraction of the Earth on 1 kg lead or the attraction of 1 kg of led

Daniel [21]

Answer:

1 kg lead to earth is greater attraction as mass of earth is much more than 1kg lead.

Explanation:

Objects with more mass have more gravity. Gravity also gets weaker with distance. So, the closer objects are to each other, the stronger their gravitational pull is. Earth's gravity comes from all its mass

7 0

3 years ago

A high jumper jumps over a bar that is 2 m above the mat. With what velocity does the jumper strike the mat in the landing area?

docker41 [41]

Answer:

The velocity with which the jumper strike the mat in the landing area is 6.26 m/s.

Explanation:

It is given that,

A high jumper jumps over a bar that is 2 m above the mat, h = 2 m

We need to find the velocity with which the jumper strike the mat in the landing area. It is a case of conservation of energy. let v is the velocity. it is given by :

$v=\sqrt{2gh}$

g is acceleration due to gravity

$v=\sqrt{2\times 9.81\ m/s^2\times 2\ m}$

v = 6.26 m/s

So, the velocity with which the jumper strike the mat in the landing area is 6.26 m/s. Hence, this is the required solution.

8 0

3 years ago

a dump truck travels 70mph for 3 hours, then for 20mph for another 2 hours in the same direction. what is the average speed the

Dmitry_Shevchenko [17]

Answer:

the average speed of the car is 170 mph.

Explanation:

Given;

initial speed, u = 70 mph

time of motion, t₁ = 3 hours

final speed, v = 20 mph

time of motion, t₂ = 2 hours

The average speed of the car is calculated as;

$v' = \frac{70(3) - 20(2)}{3-2} \\\\v' = 170 \ mph$

Therefore, the average speed of the car is 170 mph.

8 0

3 years ago

X-rays with an energy of 400 keV undergo Compton scattering with a target. If the scattered X-rays are detected at \theta = 30^{

dedylja [7]

<h2>Answer: 37.937 keV</h2>

Explanation:

<u>Photons have momentum</u>, this was proved by he American physicist Arthur H. Compton after his experiments related to the <u>scattering of photons from electrons</u> (Compton Effect or Compton Shift). In addition, energy and momentum are conserved in the process.

In this context, the Compton Shift $\Delta \lambda$ in wavelength when the photons are scattered is given by the following equation:

$\Delta \lambda=\lambda' - \lambda_{o}=\lambda_{c}(1-cos\theta)$ (1)

Where:

$\lambda_{c}=2.43(10)^{-12} m$ is a constant whose value is given by $\frac{h}{m_{e}.c}$ , being $h=4.136(10)^{-15}eV.s$ the Planck constant, $m_{e}$ the mass of the electron and $c=3(10)^{8}m/s$ the speed of light in vacuum.