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xenn [34]
3 years ago
13

Help me please!! 15points

Physics
1 answer:
Romashka-Z-Leto [24]3 years ago
4 0

Explanation:

Acceleration is the change in speed over change in time.

a = Δv / Δt

a. The car's acceleration is:

a = (80 km/h − 0 km/h) / 10 s

a = 8 km/h/s

So every second, the speed increases by 8 km/h.

b. The cyclist's acceleration is:

a = (16 m/s − 4.0 m/s) / 5.6 s

a = 2.1 m/s²

c. The stone's speed is:

10.0 m/s² = (v − 0 m/s) / 3.5 s

v = 35 m/s

d. The time is:

1.6 m/s² = (10 m/s − 0 m/s) / t

t = 6.3 s

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A dentist uses a concave mirror (focal length 2.5 cm) to examine some teeth. If the distance from the object to the mirror is 1.
AysviL [449]

Answer:

2.28

Explanation:

From mirror formula,

1/f = 1/u+1/v .......... Equation 1

Where f = focal length of the mirror, v = image distance, u = object distance.

Note: The focal length mirror is positive.

make v the subject of the equation,

v = fu/(u-f)............ Equation 2

Given: f = 2.5 cm, u = 1.4 cm

Substitute into equation 2

v = 2.5(1.4)/(1.4-2.5)

v = 3.5/-1.1

v = -3.2 cm.

Note: v is negative because it is a virtual image.

But,

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M = 3.2/1.4

M = 2.28.

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3 0
3 years ago
A cheetah can accelerate from rest at the rate of 4m /s
lesya [120]
Acceleration of cheetah (a) = 4m/s²
time = 10s
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distance travelled = s

v = u +at = 0 + 10×4 = 40m/s
s = (v²-u²)/2a = 40²/(2×4) = 1600/8 = 200m
   
6 0
3 years ago
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alexandr1967 [171]

Answer:

its C. The north pole of one magnet attracts the south pole of another

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4 0
3 years ago
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Two boxes are at rest on a smooth, horizontal surface. The boxes are in contact with one another. If box 1 is pushed with a forc
Maslowich

Answer:

mass of box 1 = 2.20 kg

mass of box 2 = 5.93 kg

Explanation:

Let the mass of box 1 and box 2 is respectively

m_1 and m_2

so we will have

Force applied on box 1 then acceleration

a = \frac{F}{m_1 + m_2}

1.50 = \frac{12.2}{m_1 + m_2}

m_1 + m_2 = 8.13

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F_n = m_2a

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m_2 = 5.93 kg

now we have

m_1 = 2.20 kg

8 0
3 years ago
In the article “Who Shaped our Behaviors? Peers or Parents?”, Judy Rich Harris suggests that __________ are the most influential
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<span>In the article “Who Shaped our Behaviors? Peers or Parents?”, Judy Rich Harris suggests that C. peers are the most influential in forming children's personalities.
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3 years ago
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