All categories

3 years ago

A ball is kicked from the top of a building with a velocity of 50 m/s and lands 165 m away from the base of the building.

Physics

1 answer:

Akimi4 [234]3 years ago

3 0

Answer:

3.1 s

Explanation:

we can assume that this motion has a horizontal projectile motion.

projectile motion happens when an object is subjected to only gravity. Gravity acts to influence the vertical motion of the projectile, it makes a vertical acceleration.

The horizontal motion of the projectile is the result of the constant velocity of the object.We assume no acceleration in the horizontal direction.

applying motion equations

where

s - distance

u - initial velocity

a-acceleration

t - time

s = ut + (1/2)at²

→ 165 = 50t + 0 (as no acceleration is in horizontal direction)

t = 3.1 s

You might be interested in

Help me please i dont understand

alexandr402 [8]

Option A is the correct answer.

5 0

2 years ago

Jane has a mass of 55 kg and his body covers 700 nails with a surface area of 1.00 mm,

Oksana_A [137]

We have,

Jane mass is 55 kg
His body covered with 700 nails all of them having a surface area of 1.00 mm² each = 700 × 1 = 700 mm² = 700/1000000 = 7/10000

We know that,

Pressure = Force/Area

Let's calculate force as we already have area;

F = ma
F = 55 × 9.8 { Acceleration due to gravity }
F = 539 N

Now, if should she would be on 700 nails then pressure will be;

P = F/A
P = 539/7 × 10000
P = 5390000/7
P = 770,000 Pascal

And if should would be on a 1 nail only,

P = F/A
P = 539/1 × 1000000
P = 539000000 Pascal

As, you can notice yourself that the pressure will be so high with only 1 nail and because of this, nail will pass through jane's body.

6 0

2 years ago

Where is the near point of an normal eye when accidentally wear a contact lens with a power of +2.0 diopters?

Lerok [7]

Answer:

The near point of an eye with power of +2 dopters, u' = - 50 cm

Given:

Power of a contact lens, P = +2.0 diopters

Solution:

To calculate the near point, we need to find the focal length of the lens which is given by:

Power, P = $\frac{1}{f}$

where

f = focal length

Thus

f = $\frac{1}{P}$

f = $\frac{1}{2}$ = + 0.5 m

The near point of the eye is the point distant such that the image formed at this point can be seen clearly by the eye.

Now, by using lens maker formula:

$\frac{1}{f} = \frac{1}{u} + \frac{1}{u'}$

where

u = object distance = 25 cm = 0.25 m = near point of a normal eye

u' = image distance

Now,

$\frac{1}{u'} = \frac{1}{f} - \frac{1}{u}$

$\frac{1}{u'} = \frac{1}{0.5} - \frac{1}{0.25}$

$\frac{1}{u'} = \frac{1}{f} - \frac{1}{u}$

Solving the above eqn, we get:

u' = - 0.5 m = - 50 cm

7 0

3 years ago

The 1.5kg ball is launched straight upward with an initial velocity of 7m/s. What is the maximum height it will reach?

Temka [501]

Answer:

h = 2.5 m

Explanation:

Given that,

Mass of a ball, m = 1.5 kg

Initial velocity of the ball, u = 7 m/s

We need to find the maximum height reached by the ball. Let it is be h. Using the conservation of energy to find it such that,

$mgh=\dfrac{1}{2}mu^2\\\\h=\dfrac{u^2}{2g}$

Put all the values,

$h=\dfrac{7^2}{2\times 9.8}\\\\=2.5\ m$

So, it will reach to a height of 2.5 m.

8 0

3 years ago

what is the transfer of heat energy by direct contact. A . convection b. radiation c. thermal or heat and d. conduction

katrin2010 [14]

Answer:

d. conduction

Explanation:

Conduction involves the transfer of electric charge or thermal energy due to the movement of particles. When the conduction relates to electric charge, it is known as electrical conduction while when it relates to thermal energy, it is known as heat conduction.

In the process of heat conduction, thermal energy is usually transferred from fast moving particles to slow moving particles during the collision of these particles. Also, thermal energy is typically transferred between objects that has different degrees of temperature and materials (particles) that are directly in contact with each other but differ in their ability to accept or give up electrons.

Any material or object that allow the conduction (transfer) of electric charge or thermal energy is generally referred to as a conductor. Conductors include metal, steel, aluminum, copper, frying pan, pot, spoon etc.

In conclusion, conduction typically involves the transfer of heat energy by direct contact between two or more conductors such as a pot and electric cooker.

6 0

2 years ago

Read 2 more answers