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Tanya [424]
3 years ago
10

A car accelerates from 0 m/s to 20 m/s in 5 seconds,

Physics
1 answer:
____ [38]3 years ago
8 0

Answer:

4

Explanation:

20-0=20 m/s

20/5=4 m/s2

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Halley's comet orbits the sun roughly once every 76 years. It comes very close to the surface of the Sun on its closest approach
Licemer1 [7]

Answer:

r1 = 5*10^10 m , r2 = 6*10^12 m

v1 = 9*10^4 m/s

From conservation of energy

K1 +U1 = K2 +U2

0.5mv1^2 - GMm/r1 = 0.5mv2^2 - GMm/r2

0.5v1^2 - GM/r1 = 0.5v2^2 - GM/r2

M is mass of sun = 1.98*10^30 kg

G = 6.67*10^-11 N.m^2/kg^2

0.5*(9*10^4)^2 - (6.67*10^-11*1.98*10^30/(5*10^10)) = 0.5v2^2 - (6.67*10^-11*1.98*10^30/(6*10^12))

v2 = 5.35*10^4 m/s

3 0
3 years ago
3. A dog walks a distance of 100 ft. in 20 s of time. What is the dog's
natta225 [31]
The answer is A.
100/20=5
8 0
3 years ago
Read 2 more answers
A 115 g hockey puck sent sliding over ice is stopped in 15.1 m by the frictional force on it from the ice.
Hoochie [10]

Answer:

(a) Ff = 0.128 N

(b μk = 0.1135

Explanation:

kinematic analysis

Because the hockey puck  moves with uniformly accelerated movement we apply the following formulas:

vf=v₀+a*t Formula (1)

d= v₀t+ (1/2)*a*t² Formula (2)

Where:  

d:displacement in meters (m)  

t : time in seconds (s)

v₀: initial speed in m/s  

vf: final speed in m/s  

a: acceleration in m/s

Calculation of the acceleration of the  hockey puck

We apply the Formula (1)

vf=v₀+a*t      v₀=5.8 m/s ,  vf=0

0=5.8+a*t

-5.8 = a*t

a= -5.8/t   Equation (1)

We replace a= -5.8/t in the Formula (2)

d= v₀*t+ (1/2)*a*t²   ,  d=15.1 m ,  v₀=5.8 m/s

15.1 = 5.8*t+ (1/2)*(-5.8/t)*t²  

15.1= 5.8*t-2.9*t

15.1= 2.9*t

t = 15.1 / 2.9

t= 5.2 s

We replace t= 5.2 s in the equation (1)

a= -5.8/5.2

a= -1.115 m/s²

(a) Calculation of the  frictional force (Ff)

We apply Newton's second law

∑F = m*a    Formula (3)

∑F : algebraic sum of the forces in Newton (N)

m : mass in kilograms (kg)

a : acceleration in meters over second square (m/s²)

Look at the free body diagram of the  hockey puck in the attached graphic

∑Fx = m*a     m= 115g * 10⁻³ Kg/g = 0.115g    ,  a= -1.12 m/s²

-Ff = 0.115*(-1.115)  We multiply by (-1 ) on both sides of the equation

Ff = 0.128 N

(b) Calculation of the coefficient of friction (μk)

N: Normal Force (N)

W=m*g= 0.115*9.8= 1.127 N : hockey puck  Weight

g: acceleration due to gravity =9.8 m/s²

∑Fy = 0

N-W=0

N = W

N =  1.127 N

μk = Ff/N

μk = 0.128/1.127

μk = 0.1135

8 0
3 years ago
A chemist needs 15.0 grams of ethanol for a reaction. If the density of ethanol is 0.789 g/ml, how many milliliters of alcohol s
harina [27]
  • Mass=15g
  • Density=0.789g/ml

\\ \bull\tt\dashrightarrow Density=\dfrac{Mass}{Volume}

\\ \bull\tt\dashrightarrow Volume=\dfrac{Mass}{Density}

\\ \bull\tt\dashrightarrow Volume=\dfrac{15}{0.789}

\\ \bull\tt\dashrightarrow Volume=19.01mL

3 0
2 years ago
What is the momentum of a 1400 kg car traveling at 25 m/s?
sveticcg [70]
<h2>Hello</h2>

The answer is:

35000Kg.\frac{m}{s}=35000N

<h2>Why?</h2>

Momentum is the quantity of movement of an object, and it's calculated using the mass and the velocity of the object. Momentum is expressed by the following formula:

p=m*v

Where:

m=mass\\v=velocity

So, calculating we have:

p=m*v=1400Kg*\frac{25m}{s}=35000Kg.\frac{m}{s}=35000N

Remember,

1N=1Kg.\frac{m}{s}

Have a nice day!

5 0
2 years ago
Read 2 more answers
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