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3 years ago

We are able to walk forward because _____.

Physics

2 answers:

Diano4ka-milaya [45]3 years ago

7 0

Cuz Of Newton’s third law, every actions there is an equal and opposite reaction.

cestrela7 [59]3 years ago

5 0

we are able to walk because of the forward and upward reaction force exerted by the earth on us.

when we walk, we push the earth backwards and downwards with our foot. We are able to do so because of the grip provided by the force of friction. The earth pushes us with an equal and opposite force as per third law of motion.Thus we are pushed by the earth in forward direction and we are able to walk.

You might be interested in

Which of the following is the same in all frames and reference?

Otrada [13]

B.Speed of light

The speed of light is used as a reference and is 3x10^8 m/s no matter what.

Hope this helps :)

7 0

3 years ago

An initially motionless test car is accelerated to 115 km/h in 8.58 s before striking a simulated deer. The car is in contact wi

hoa [83]

Answer:

a) a = 3.72 m / s², b) a = -18.75 m / s²

Explanation:

a) Let's use kinematics to find the acceleration before the collision

v = v₀ + at

as part of rest the v₀ = 0

a = v / t

Let's reduce the magnitudes to the SI system

v = 115 km / h (1000 m / 1km) (1h / 3600s)

v = 31.94 m / s

v₂ = 60 km / h = 16.66 m / s

et's calculate

a = 31.94 / 8.58

a = 3.72 m / s²

b) For the operational average during the collision let's use the relationship between momentum and momentum

I = Δp

F Δt = m v_f - m v₀

F = $\frac{m ( v_f - v_o)}{t}$

F = m [16.66 - 31.94] / 0.815

F = m (-18.75)

Having the force let's use Newton's second law

F = m a

-18.75 m = m a

a = -18.75 m / s²

4 0

3 years ago

.. A 15.0-kg fish swimming at 1.10 m>s suddenly gobbles up a 4.50-kg fish that is initially stationary. Ignore any drag effec

stira [4]

Answer:

(a) 0.846 m/s

(b) 2.097J

Explanation:

Parameters given:

Mass of big fish, M = 15 kg

Mass of small fish, m = 4.5 kg

Initial speed of big fish, U = 1.1 m/s

Initial speed of small fish, u = 0 m/s (it is stationary)

(a) We apply the principle of conservation of momentum:

Total initial momentum = Total final momentum

Since both fish have the same final speed, V, (the small fish is in the mouth of the big fish), we have:

MU + mu = (M + m)*V

(15 * 1.1) + (4.5 * 0) = ( 15 + 4.5) * V

16.5 = 19.5V

=> V = 16.5/19.5

V = 0.846 m/s

The speed of the large fish after the meal is 0.846 m/s.

(b) We need to find the change in Kinetic energy of the entire system to find the total mechanical energy dissipated.

Initial Kinetic energy:

KEini = (½ * M * U²) + (½ * m * u²)

KEini = (½ * 15 * 1.1²) + (½ * 4.5 * 0²)

KEini = 9.075 J

Final Kinetic Energy:

KEfin = (½ * M * V²) + (½ * m * V²)

KEfin = (½ * 15 * 0.846²) + (½ * 4.5 * 0.846²)

KEfin = 5.368 + 1.610 = 6.978 J

Change in kinetic energy will be:

KEfin - KEini = 9.075 - 6.978

ΔKE = 2.097 J

The energy dissipated in eating the meal is 2.097 J

5 0

3 years ago

Which statement describes a scientific theory?

PSYCHO15rus [73]

Answer:

A theory changes based on new observations and testing.

Explanation:

A scientific theory is a product of multiple trials and repeated experiments. It usually follows after carefully conducting and testing the validity of the hypothesis.

A scientific theory provides an explanation into how something behaves.

A law just states a finding will not explain it.

Most theories are tenable and can be improved upon when new observations and testing are carried out.

4 0

4 years ago

Compute the order of magnitude of the mass of a bathtub half full of pennies. (Assume the pennies are made entirely of copper.)

devlian [24]

Answer:

Mass = 873.6kg = 0.874 × 10^3 kg

Order = 3

Question:

Compute the order of magnitude of the mass of a bathtub half full of pennies.(Assume the pennies are made entirely of copper and the tub measures 1.3 m by 0.5 m by 0.3 m)

Explanation:

Given:

Dimensions of the tub = 1.3 m by 0.5 m by 0.3 m

Density of copper d = 8960kg/m^3

Mass = volume × density

Volume of tub = L×B×H = 1.3 × 0.5 × 0.3 = 0.195m^3

Since the tub is half full:

V = 0.195/2 = 0.0975m^3

Mass = 8960kg/m^3 × 0.0975m^3

Mass = 873.6kg = 0.874 × 10^3 kg

Order = 3

Note: Order of magnitude is of the form:

N = a × 10^b

Where;

b = order of magnitude

and

1/√10 </= a < √10

8 0

4 years ago