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FinnZ [79.3K]
3 years ago
5

7. How long does it take a ball rolling down a hill to change its speed from 3 m/sec to 34.5 m/sec

Physics
1 answer:
lys-0071 [83]3 years ago
8 0

The time elapsed is 9 seconds

Explanation:

The motion of the ball is a uniformly accelerated motion (a motion with constant acceleration), so we can use the following suvat equation:

v=u+at

where :

v is the final velocity  of the ball

u is the initial velocity

a is the acceleration

t is the time  elapsed

For the ball in this problem, we have:

u = 3 m/s is the initial velocity

v = 34.5 m/s is the final velocity

a=3.5m/s^2 is the acceleration

Solving for t, we find the time taken for this change in velocity:

t=\frac{v-u}{a}=\frac{34.5-3}{3.5}=9 s

Learn more about acceleration:

brainly.com/question/9527152  

brainly.com/question/11181826  

brainly.com/question/2506873  

brainly.com/question/2562700  

#LearnwithBrainly

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A 2.0 kg mass weighs 10 Newtons on planet X. what is the acceleration due to gravity on planet X? Show the work.
KengaRu [80]

Answer: The gravitational acceleration on planet X is 5 N/kg

On Earth (with the gravitational accelartion g_E) the mass of 2kg will correspond to

F_E = m\cdot g_E = 2.0 \mbox{kg}\cdot 9.8 \frac{N}{kg} = 19.6 N

On planet X we are told the same measure is only 10N. Since there is a proportional relationship between g and F, we can calculate g_X:

\frac{F_E}{g_E}=\frac{F_X}{g_X} \implies\\g_x = \frac{g_E\cdot F_X}{F_E}=\frac{9.8 N/kg \cdot 10 N }{19.6N}=5 \frac{N}{kg}

8 0
3 years ago
If an object is thrown upward at 128 feet per second from a height of 76 feet, its height S after t seconds is given by the foll
faltersainse [42]
<h2>a) Average velocity in first 4 seconds is 64 ft/s upward</h2><h2>b) Average velocity in second 4 seconds is 63.5 ft/s downward</h2>

Explanation:

a) Given S(t) = 76 + 128t − 16t²

    s(0) = 76 + 128 x 0 − 16 x 0² = 76 ft

    s(4) = 76 + 128 x 4 − 16 x 4² = 332 ft

    Displacement in 4 seconds = 332 - 76 = 256 ft

    Time = 4 - 0 = 4 s

    \texttt{Velocity = }\frac{256}{4}=64ft/s

    Average velocity in first 4 seconds is 64 ft/s upward

a) Given S(t) = 76 + 128t − 16t²

    s(4) = 76 + 128 x 4 − 16 x 4² = 332 ft

    s(8) = 76 + 128 x 8 − 16 x 8² = 78 ft

    Displacement in 4 seconds = 78 - 332 = -254 ft

    Time = 4 - 0 = 4 s

    \texttt{Velocity = }\frac{-254}{4}=-63.5ft/s

    Average velocity in second 4 seconds is 63.5 ft/s downward

3 0
3 years ago
True or False: We have a limited amount of fossil fuels.<br> True.<br> False.
Nina [5.8K]
True because we have limited amount if it
4 0
3 years ago
A baseball is hit with a bat. The direction of the ball is completely reversed and its speed is doubled. If the actual contact w
alexdok [17]
Before the impact, let the velocity of the baseball was v m/s.

After being hit by the bat its velocity is -2v
So, change in velocity, Deltav=v-(-2v)=3v
Acceleration is defined as the rate of change in velocity, i.e. actual change in velocity divided by the time taken to change it. Time taken to change velocity is the time of actual contact of the bat and ball, i.e. 0.31 s.

a=(Deltav)/(Deltat)
=(3v)/0.37
Therefore, a/v=3/0.31=9.7 s^-1
So, the ratio of acceleration of the baseball to its original velocity is 9.7.
8 0
3 years ago
Read 2 more answers
the density of a steel is 7.8.find the mass of steel cube of side 10 cm. find volume of steel if the mass is 8kg​
lukranit [14]

Answer:

Mass of the steel cube =  7800 kg

Volume of the steel  = 1.025 cubic centimetre

Explanation:

Given:

The density of the steel   =  7.8

Side of the cube = 12 cm

<u>(1)The mass of steel cube :</u>

We know that,

Density  = \frac{Mass}{Volume}

We are given with density and sides of the cube

then volume of the cube

= (side)^3

= 10^3

= 1000 cubic centimetre

Now

7.8 = \frac{mass}{1000}

mass = 7.8 \times 1000

mass =  7800 kg

<u>(2)volume of steel:</u>

Given the mass  = 8 kg

Density  = \frac{Mass}{Volume}

Substituting the values

7.8 = \frac{8}{volume}

volume = \frac{8}{7.8}

volume = 1.025 cubic centimetre

3 0
2 years ago
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