Free fall

How long does the stone fall freely into a depth of 80m? What speed will it hit the bottom of the abyss?

Result

t =  4 s
v =  40 m/s

Solution:

s=12gt2 g=10 m/s2 s=80 m t=2⋅ sg=2⋅ 8010=4 ss=\dfrac{ 1 }{ 2 } g t^2 \ \\ g=10 \ \text{m/s}^2 \ \\ s=80 \ \text{m} \ \\ t=\sqrt{ \dfrac{ 2 \cdot \ s }{ g } }=\sqrt{ \dfrac{ 2 \cdot \ 80 }{ 10 } }=4 \ \text{s}
v=g⋅ t=10⋅ 4=40 m/sv=g \cdot \ t=10 \cdot \ 4=40 \ \text{m/s}

Try another example


Our examples were largely sent or created by pupils and students themselves. Therefore, we would be pleased if you could send us any errors you found, spelling mistakes, or rephasing the example. Thank you!





Leave us a comment of this math problem and its solution (i.e. if it is still somewhat unclear...):

Showing 0 comments:
1st comment
Be the first to comment!
avatar




Tips to related online calculators
Do you want to convert velocity (speed) units?
Do you want to convert time units like minutes to seconds?

Following knowledge from mathematics are needed to solve this word math problem:

Next similar math problems:

  1. Free fall
    volny_pad_2_ap The free fall body has gone 10m in the last 0.5s. Find the body speed at the moment of impact.
  2. Bomber
    tu-160 The aircraft flies at an altitude of 4100 m above the ground at speed 777 km/h. At what horizontal distance from the point B should be release any body from the aircraft body to fall into point B? (g = 9.81 m/s2)
  3. Acceleration
    caR The car accelerates at rate 0.5m/s2. How long travels 400 meters and what will be its speed?
  4. Gravitation
    vodorovny_vrh From the top of the 80m high tower, the body is thrown horizontally with an initial speed of 15 m/s. At what time and at what distance from the foot of the tower does the body hit the horizontal surface of the Earth? (use g = 10 ms-2)
  5. Skid friction
    trenie Find the smallest coefficient of skid friction between the car tires and the road so that the car can drive at a 200 m radius at 108 km/h and does not skid.
  6. Abyss
    Mountain Stone was pushed into the abyss: 2 seconds after we heard hitting the bottom. How deep is the abyss (neglecting air resistance)? (gravitational acceleration g = 9.81 m/s2 and the speed of sound in air v = 343 m/s)
  7. Wavelength
    wave_length Calculate the wavelength of the tone frequency 11 kHz if the sound travels at speeds of 343 m/s.
  8. Brakes
    pneu The braking efficiency of a passenger car is required to stop at 12.5 m at an initial speed of 40 km/h. What is the acceleration braking by brakes?
  9. Circular motion
    mass_point_circle Mass point moves moves uniformly in a circle with radius r = 3.4 m angular velocity ω = 3.6 rad/s. Calculate the period, frequency, and the centripetal acceleration of this movement.
  10. Theorem prove
    thales_1 We want to prove the sentence: If the natural number n is divisible by six, then n is divisible by three. From what assumption we started?
  11. G forces
    car_crash Calculate deceleration of car (as multiple of gravitational acceleration g = 9.81 m/s2) which occurs when a car in a frontal collision slows down uniformly from a speed 111 km/h to 0 km/h in 1.2 meters trajectory.
  12. Flywheel
    zotrvacnik Flywheel turns 450 rev/min (RPM). Determine the magnitude of the normal acceleration of the flywheel point which are at a distance of 10 cm from the rotation axis.
  13. Third member
    seq_6 Determine the third member of the AP if a4=93, d=7.5.
  14. GP members
    sequence_geo_8 The geometric sequence has 10 members. The last two members are 2 and -1. Which member is -1/16?
  15. Five harvests
    zrno In the seed company, they know that, out of 100 grains of a new variety, they get an average of 2000 grains after harvest. Approximately how many grains do they get out of 100 grains after five harvests?
  16. Parametric equation
    line Find the parametric equation of a line with y-intercept (0,-4) and a slope of -2.
  17. Pre účinnosť
    motion2_6 Pre účinnosť bŕzd osobného vozidla je predpísané, že automobil pohybujúci sa po vodorovnej vozovke rýchlosťou 40km. H musí zastaviť na dráhe 15,4 m. Aké veľké je pritom spomalenie automobilu?