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Marat540 [252]
3 years ago
13

Joaquin is at rest at the top of a hill on a skateboard. Four seconds later, he reaches the bottom of the hill at a final veloci

ty of 20 m/s. What was his acceleration?
Physics
1 answer:
Andre45 [30]3 years ago
8 0

Explanation:

Given: Initial Velocity=0

Final Velocity= 20 m/s

Time= 4 s

Accleration: Unknowns

Use kinematic equation

v   _{f} = v _{i} + at

20 = 0 + at

\frac{20m}{s}  = a(4s)

a =  \frac{5m}{ {s}^{2} }

so a = 5 m/s^2

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A car travels 50 km in 25 km /h and then travels 60km with a velocity 20 km/h and then travels 60km with a velocity 20 km/h in t
Butoxors [25]

Answer:

v = 21.25 km/h

The average velocity is 21.25km/h

Explanation:

Average velocity = total displacement/time taken

v = d/t

Given;

A car travels 50 km in 25 km /h

d1 = 50km

v1 = 25km/h

time taken = distance/velocity

t1 = d1/v1

t1 = 50/25 = 2 hours

and then travels 60km with a velocity 20 km/h

d2 = 60km

v2 = 20km/h

t2 = d2/v2 = 60/20

t2 = 3 hours

and then travels 60km with a velocity 20 km/h in the same direction

d3 = 60km

v3 = 20km/h

t3 = d3/v3 = 60/20

t3 = 3 hours

Average velocity = total displacement/total time taken

v = (d1+d2+d3)/(t1+t2+t3)

v = (50+60+60)/(2+3+3)

v = 170/8

v = 21.25 km/h

The average velocity is 21.25km/h

3 0
3 years ago
Lake point tower in chicago is the tallest apartment building in the united states. suppose you take the elevator from street le
notka56 [123]

Using the idea of work done under gravity, the height of the building is 187 m.

<h3>Work done in a gravitational field</h3>

We must recall that the work done in a gravitational field is given by; mgh

m= mass

g = acceleration due to gravity

h = height

mass = 60.0 kg

Workdone = 1.15x10^5 J

W = mgh

h = W/mg

h =  1.15x10^5 J/60.0 kg * 9.8 ms-2

h = 187 m

Learn more about work done: brainly.com/question/13662169?

7 0
2 years ago
Type your answer...
ArbitrLikvidat [17]

Answer:

50.4÷1.18= 42.7m/s as speed is equal to the distance over the time taken

3 0
3 years ago
Investigator Daniels is working on the scene of a suspected arson on a rainy evening. The site of the fire was a mechanic's gara
allsm [11]

Answer:

Rainy

Explanation:

It is the only one that has nothing to do with the case

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2 years ago
Part A Every force has one and only one 3rd law pair force. Every force has one and only one 3rd law pair force. true false Requ
Scorpion4ik [409]

Answer:

Explanation:

Part A

Every force has one and only  pair force , according to 3 rd law

It is true , the pair force has equal magnitude .

Part B

The two forces in each pair act in opposite directions.

It is true .

The pair forces are equal and act in opposite direction .

Part C

The two forces in each pair can either both act on the same body or they can act on different bodies.

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