1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Effectus [21]
3 years ago
5

Experimenting with free fall, Mariana observes that her baseball takes 1.5 s to travel the last 30m before hitting the ground. F

rom what height above the ground did Mariana drop the ball?
Physics
1 answer:
Art [367]3 years ago
4 0

Answer:

37.8 m

Explanation:

At point 0, the ball is at height y₀.

At point 1, the ball is at height 30 m.

At point 2, the ball is at height 0 m.

Given:

y₁ = 30 m

y₂ = 0 m

v₀ = 0 m/s

a = -10 m/s²

t₂ − t₁ = 1.5 s

Find: y₀

Use constant acceleration equation.

y = y₀ + v₀ t + ½ at²

Evaluate at point 1.

y₁ = y₀ + v₀ t₁ + ½ at₁²

30 m = y₀ + (0 m/s) t₁ + ½ (-10 m/s²) t₁²

30 = y₀ − 5t₁²

Evaluate at point 2.

y₂ = y₀ + v₀ t₂ + ½ at₂²

0 m = y₀ + (0 m/s) t₂ + ½ (-10 m/s²) t₂²

0 = y₀ − 5t₂²

y₀ = 5t₂²

Substitute:

y₀ = 5 (1.5 + t₁)²

y₀ = 5 (2.25 + 3t₁ + t₁²)

y₀ = 11.25 + 15t₁ + 5t₁²

30 = 11.25 + 15t₁ + 5t₁² − 5t₁²

30 = 11.25 + 15t₁

t₁ = 1.25

30 = y₀ − 5t₁²

30 = y₀ − 5(1.25)²

y₀ ≈ 37.8

You might be interested in
If an object moving at 12 m/s has a kinetic energy of 72 j what is the mass
EleoNora [17]
Simply, apply the formula E = \frac{1}{2}mv^{2} and insert the values of m = mass, v = velocity and E = Energy.
The result will be 72J =  \frac{1}{2}m(12m/s)^{2}, m = 1 kg
5 0
3 years ago
A 5.0-μC charge is placed at the 0 cm mark of a meter stick and a -4.0 μC charge is placed at the 50 cm mark. At what point on a
Maksim231197 [3]

Answer:

The distance from charge 5 μ C = 26.45 cm and the distance from - 4 μ C is 23.55 cm.

Explanation:

Given that

q₁ = 5 μ C

q₂ = - 4 μ C

The distance between charges = 50 cm

d= 50 cm

Lets take at distance x from the charge μ C ,the electrical field is zero.

That is why the distance from the charge - 4 μ C =  50 - x cm

We know that ,electric field is given as

E=K\dfrac{q}{r^2}

K\dfrac{5\ \mu}{x^2}=K\dfrac{4\mu }{(50-x)^2}\\\\\dfrac{5}{x^2}=\dfrac{4 }{(50-x)^2}\\\\\\5(50-x)^2=4x^2\\(50-x)^2=0.8x^2\\\\50-x =0.89x\\\ x=\dfrac{50}{1.89}\ cm\\\\\\x=26.45\ cm\\

Therefore the distance from charge 5 μ C = 26.45 cm and the distance from - 4 μ C is 23.55 cm.

3 0
3 years ago
Ten high-technology batteries are tested for 200 hours each. One failed at 20 hours; another failed at 140 hours; all others com
Bas_tet [7]

Answer:

Failure rate   = 20%

MTBF = 880 hours

Explanation:

given data

batteries = 10

tested = 200 hours

one failed = 20 hours

another fail at =  140 hours

solution

we know that Mean Time between Failures is express as = (Total up time) ÷  (number of breakdowns)    ....................1

so here Total up time will be

Total up time = 200 × 10

Total up time = 2000

and here

Number of breakdown = 1 at 20 hour and another at 140 hour = 2

so it will be  = (Total up time) ÷ (number of breakdowns)      .......2

=  \frac{2000}{2}   =  1000  

so here gap between occurrences is

gap between occurrences=  140 - 20

gap between occurrences = 120 hour

and

MTBF  will be

MTBF = 1000 - 120

MTBF = 880 hours  

and

Failure rate (FR)  will be

Failure rate (FR) =  1 ÷ MTBF    ................3

Failure rate (FR) = R÷T     ......................4

as here R is the number of failures and T is total time

so Failure rate (FR)  = 20%

4 0
3 years ago
When the mass of an object decreases, the force of gravity - Remains Unchanged - Decreases - increases - Becomes irregular
Gwar [14]
The force of gravity decreases
5 0
3 years ago
Read 2 more answers
a man crossed a road 8.25m wide at a speed of 2.01m/s,how long does it take to get man to cross the road​
Svetradugi [14.3K]

Answer:

t = 4.1 seconds

Explanation:

It is given that,

Width of road which is to be crossed by a man is 8.25 m, it means it is distance to be covered.

Speed of man is 2.01 m/s

We need to find the time taken by the man to cross the road. It is a concept of speed. Speed of a person is given by total distance covered divided by time taken. So,

v=\dfrac{d}{t}

t is time taken

t=\dfrac{d}{v}\\\\t=\dfrac{8.25}{2.01}\\\\t=4.1\ s

So, the time taken by the man to cross the road is 4.1 seconds.

5 0
3 years ago
Other questions:
  • Three identical point charges ( 2.0 nc are placed at the corners of an equilateral triangle with sides of 2.0-m length. if the e
    8·1 answer
  • An object moves 2.5 m. This is an example of a _______.
    6·2 answers
  • The half-life of caffeine is 5 hours. If you ingested a 30 oz Big Gulp, after how much time will have to pass before you have un
    15·1 answer
  • 2. If a rock fell down a cliff and hit the bottom of the ravine at 4 seconds, how fast was the rock
    7·2 answers
  • Alan leaves Los Angeles at 8:00 a.m. to drive to San Francisco, 400 mi away. He travels at a steady 46.0 mph . Beth leaves Los A
    9·1 answer
  • A 2-kg object is moving 6 m/s in a horizontal direction.
    6·1 answer
  • Which best describes the motion of air particles when a transverse wave passes through them?
    11·1 answer
  • A friend throws a heavy ball toward you while you are standing on smooth ice. You can either catch the ball or deflect it back t
    5·1 answer
  • can someone help me answer this correctly in the next 20 minutes? I’ll give out a brainliest if you can answer it right :)
    13·1 answer
  • Which feature of a heating curve indicates a change of state
    10·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!