7. A bowling ball rolled with a force of 15 N accelerates at a rate of 3 m/sec, a second ball rolled

A cancer or cancerous tumour on the skin<br> as a result of extensive exposure to UV rays.

nekit [7.7K]

Answer:

Almost all skin cancers (approximately 99% of non-melanoma skin cancers and 95% of melanoma) are caused by too much UV radiation from the sun or other sources such as solaria (solarium, sunbeds, and sun lamps).

Explanation:

Skin cancer develops in the cells in the epidermis – the top or outer layer of the skin. UV radiation is made up of UVA and UVB rays which are able to penetrate the skin and cause permanent damage to the cells below:

UVA penetrates deeply into the skin (the dermis) causing genetic damage to cells, photo-ageing (wrinkling, blotchiness etc) and immune-suppression.

UVB penetrates into the epidermis (top layer of the skin) causing damage to the cells. UVB is responsible for sunburn – a significant risk factor for skin cancer, especially melanoma.

If the body is unable to repair this damage the cell can begin to divide and grow in an uncontrolled way. This growth can eventually form a tumor.

UVA and UVB both contribute to sunburn, skin ageing, eye damage and melanoma and other skin cancers.

3 0

4 years ago

A blacksmith hammers a hot piece of iron while making a tool.How does the force due to hammering effect the piece of iron ???

Whitepunk [10]

Answer:

The force due to hammering changes the shape of the piece of iron

Explanation:

How hard you hammer the iron while it is hot will cause the iron to change shape or reform the way you want it.

4 0

3 years ago

Which statement correctly describes mass-energy equivalence?

Umnica [9.8K]

<span>Mass is inversely proportional to energy. The larger the mass, the smaller will be the energy.</span>

8 0

3 years ago

An electron collides elastically with a stationary hydrogen atom. The mass of the hydrogen atom is 1837 times that of the electr

tamaranim1 [39]

Answer:

$\frac{K_{h}}{K_{i}} = = 2.17 \times 10^{-3}$

Explanation:

As we know that there is no external force on the system of hydrogen atom and electron so we will say momentum is conserved

so we will have

$m_1 v_{1i} = m_1v_{1f} + m_2v_{2f}$

here we know that

$m_1 = m$

$m_2 = 1837m$

now we have

$m v = mv_{1f} + 1837v_{2f}$

$v_{1f} + 1837v_{2f} = v$

also we know that

$v_{2f} - v_{1f} = v$

now we will have

$1838v_{2f} = 2v$

$v_{2f} = \frac{v}{919}$

now we need to find the ratio of kinetic energy of hydrogen atom with initial kinetic energy

so it is given as

$\frac{K_{h}}{K_{i}} = \frac{\frac{1}{2}(1837m)(\frac{v}{919})^2}{\frac{1}{2}mv^2}$

$\frac{K_{h}}{K_{i}} =\frac{1837}{919^2}$

$\frac{K_{h}}{K_{i}} = = 2.17 \times 10^{-3}$

4 0

4 years ago

The force needed to keep a car from skidding on a curve varies inversely as the radius of the curve and jointly as the weight of

motikmotik

Explanation:

It is given that, the force needed to keep a car from skidding on a curve varies inversely as the radius of the curve and jointly as the weight of the car and the square of the car's speed such that,

$F\propto \dfrac{mgv^2}{r}$

$F=\dfrac{kmgv^2}{r}$

mg is the weight of the car

r is the radius of the curve

v is the speed of the car

Case 1.

F = 640 pounds

Weight of the car, W = mg = 2600 pound

Radius of the curve, r = 650 ft

Speed of the car, v = 40 mph

$640=\dfrac{k(2600)(40)^2}{650}$

k = 0.1

Case 2.

Radius of the curve, r = 750 ft

Speed of the car, v = 30 mph

$F=\dfrac{0.1\times 2600\times (30)^2}{750}$

F = 312 N

Hence, this is the required solution.

6 0

3 years ago