How long will a trip take in hours of you travel 450kmat an average speed of 80 km/hr

Which of the following observations represent conclusive evidence of an interaction? (Select all that apply.)

9966 [12]

Answer:

a,b,d and e are correct.

Explanation:

a) Change of temperature without change of velocity is a conclusive evidence of an interaction. As the temperature of a body will only change if heat energy is flows in or out of the body with surrounding. So, option a) is correct.

b) Change of the direction without change of speed is an evidence of an interaction. The direction changes when the object is under a perpendicular acceleration acceleration which clearly means the particle is interacting or external force applied. So, option b is correct.

d) Change of shape or configuration without change of velocity is conclusive evidence of an interaction. The shape can change only if external stress is applied on the particle. So, Option d is correct.

e) Change of identity without change of velocity is a conclusive evidence of an interaction. The identity of an object can only change if it interacts with surroundings. So, option e is correct

Therefore the only incorrect option is c .

6 0

3 years ago

Estimate how fast your hair grows, in units of m/s, assuming it takes 30 days for your hair to grow 1 inch. note that 1 inch =2.

dedylja [7]

Answer:

1) 9.8×10⁻⁹ m/s

2) 50970.3238656 L

Explanation:

1) In 30 days hair grows 1 inch

1 inch = 2.54 cm

1 cm = 0.01 m

2.54 cm = 2.54 × 0.01 m

⇒2.54 cm = 0.0254 m

30 days = 30×24×60×60 = 2592000 seconds

Speed = Distance / Time

$\text{Speed}=\frac{0.0254}{2592000}=9.8\times 10^{-9}\ m/s$

Speed at which hair grows is 9.8×10⁻⁹ m/s

2) 1 ft = 0.3048 m

0.3048 m = 30.48 cm

1 ft = 30.48 cm

15 ft = 15×30.48 = 457.2 cm

8 ft = 8×30.48 = 243.84 cm

Volume of water in pool = Length × Width × Depth

⇒Volume of water in pool = 457.2×457.2×243.84

⇒Volume of water in pool = 50970323.8656 cm³

or

Volume of water in pool = 15×15×8 = 1800 ft³

1 ft³ = 30.48³ cm³

1800 ft³ = 30.48³ × 1800 = 50970323.8656 cm³

Converting to liters

1 L = 1000 cm³

0.001 L = 1 cm³

50970323.8656 cm³ = 50970323.8656×0.001 = 50970.3238656 L

Volume of water in pool is 50970.3238656 L

6 0

3 years ago

We can model a pine tree in the forest as having a compact canopy at the top of a relatively bare trunk. Wind blowing on the top

notka56 [123]

Answer:

A,)FD= 114.1N

B)Torque=798.5Nm

Explanation:

We can model a pine tree in the forest as having a compact canopy at the top of a relatively bare trunk. Wind blowing on the top of the tree exerts a horizontal force, and thus a torque that can topple the tree if there is no opposing torque. Suppose a tree's canopy presents an area of 9.0 m^2 to the wind centered at a height of 7.0 m above the ground. (These are reasonable values for forest trees.)

If the wind blows at 6.5 m/s, what is the magnitude of the drag force of the wind on the canopy? Assume a drag coefficient of 0.50 and the density of air of 1.2 kg/m^3

B)What torque does this force exert on the tree, measured about the point where the trunk meets the ground?

A)The equation of Drag force equation can be expressed below,

FD =[ CD × A × ρ × (v^2/ 2)]

Where CD= Drag coefficient for cone-shape = 0.5

ρ = Density

Area of of the tree canopy = 9.0 m^2

density of air of = 1.2 kg/m^3

V= wind velocity= 6.5 m/s,

If we substitute those values to the equation, we have;

FD =[ CD × A × ρ × (v^2/ 2)]

F= [ 0.5 × 9.0 m^2 × 1.2 kg/m^3 ( 6.5 m/s/ 2)]

FD= 114.1N

B) the torque can be calculated using below formula below

Torque= (Force × distance)

= 114.1 × 7

= 798.5Nm

8 0

3 years ago

Quick puzzle question. If god created the universe who created god?

mrs_skeptik [129]

Answer:

My mom always told me he was just there

Explanation:

4 0

3 years ago

Read 2 more answers

What is the equation describing the motion of a mass on the end of a spring which is stretched 8.8 cm from equilibrium and then

Sedbober [7]

Answer:

$x=(0.088m)\cos(\sqrt{\frac{k}{m} } t)$

Explanation:

We first identify the elements of this simple harmonic motion:

The amplitude A is 8.8cm, because it's the maximum distance the mass can go away from the equilibrium point. In meters, it is equivalent to 0.088m.

The angular frequency ω can be calculated with the formula:

$\omega =\sqrt{\frac{k}{m}}$

Where k is the spring constant and m is the mass of the particle.

Now, since the spring starts stretched at its maximum, the appropriate function to use is the positive cosine in the equation of simple harmonic motion:

$x=A\cos(\omega t)$

Finally, the equation of the motion of the system is:

$x=(0.088m)\cos(\omega t)$

or

$x=(0.088m)\cos(\sqrt{\frac{k}{m} } t)$

7 0

3 years ago