S = ut + $\frac{1}{2}at^2$, but u = 0, thus 9 = $\frac{1}{2}\times a \times 3^2$ $\rightarrow$ a = 2m/s2
johnmulu answered the question on February 13, 2017 at 06:34
- A bullet is fired horizontally from a platform 15 m high. If the initial speed is 300 m/s-1(Solved)
A bullet is fired horizontally from a platform 15 m high. If the initial speed is 300 m/s-1, determine the maximum horizontal distance covered by the bullet.
Date posted: February 11, 2017. Answers (1)
- A bullet moving at a velocity of 300 ms-1 hits a tree trunk of diameter 50 cm. It emerges from the opposite side with a velocity of 150 ms-1(Solved)
A bullet moving at a velocity of 300 ms-1 hits a tree trunk of diameter 50 cm. It emerges from the opposite side with a velocity of 150 ms-1. Determine the average deceleration of the bullet in the trunk.
Date posted: February 11, 2017. Answers (1)
- A bullet is fired horizontally at a target. Neglecting air resistance give a reason why the horizontal acceleration of the bullet is zero (Solved)
A bullet is fired horizontally at a target. Neglecting air resistance give a reason why the horizontal acceleration of the bullet is zero.
Date posted: February 11, 2017. Answers (1)
- An object dropped from a height h, attains a velocity of 6 ms-1 just before hitting the ground. Find the value of h(Solved)
An object dropped from a height h, attains a velocity of 6 ms-1 just before hitting the ground. Find the value of h.
Date posted: February 11, 2017. Answers (1)
- A body moving initially at 50m/s decelerates uniformly at 2 ms-2 until it comes to rest(Solved)
A body moving initially at 50m/s decelerates uniformly at 2 ms-2 until it comes to rest. What distance does it cover from the time it started decelerated?
Date posted: February 11, 2017. Answers (1)
- A pipe of radius 6 mm is connected to another pipe of radius 9 mm. If water flows in wider pipe at the speed of 2 ms-1, what is the speed in the narrower pipe?(Solved)
A pipe of radius 6 mm is connected to another pipe of radius 9 mm. If water flows in wider pipe at the speed of 2 ms-1, what is the speed in the narrower pipe?
Date posted: February 11, 2017. Answers (1)
- Start Bernoulli's principle(Solved)
Start Bernoulli's principle.
Date posted: February 11, 2017. Answers (1)
- Water flows in horizontal smooth pipe. State the changes that would be observed in the nature of the flow if the speed of the water(Solved)
Water flows in horizontal smooth pipe. State the changes that would be observed in the nature of the flow if the speed of the water is steadily increased from low to high value.
Date posted: February 11, 2017. Answers (1)
- State how the pressure in moving fluid varies with the speed of the fluid(Solved)
State how the pressure in moving fluid varies with the speed of the fluid.
Date posted: February 11, 2017. Answers (1)
- State one factor that affects the speed of sound in solid(Solved)
State one factor that affects the speed of sound in solid.
Date posted: February 11, 2017. Answers (1)
- A boy standing in front of a cliff blows a whistle and hears the echo after 0.5 s. He then moves 17 metres further away from the cliff and blows the whistle again(Solved)
A boy standing in front of a cliff blows a whistle and hears the echo after 0.5 s. He then moves 17 metres further away from the cliff and blows the whistle again. He now hears the echo after 0.6 s. Determine the speed of the sound.
Date posted: February 11, 2017. Answers (1)
- A soldier standing some distance from a wall, blow a whistle and hears its echo 1.8 seconds later. How far is the wall from the soldier?(Solved)
A soldier standing some distance from a wall, blow a whistle and hears its echo 1.8 seconds later. How far is the wall from the soldier? (Speed of sound in air is 330ms-1)
Date posted: February 11, 2017. Answers (1)
- An electronic siren producing sound continuously at a certain frequency is dropped from the top to a deep hole(Solved)
An electronic siren producing sound continuously at a certain frequency is dropped from the top to a deep hole. State and explain what is observed about the pitch of the sound reaching the observer at the top.
Date posted: February 11, 2017. Answers (1)
- A girl standing 600 m away from a cliff bangs two pieces of wood together and hears an echo 3.5 seconds later(Solved)
A girl standing 600 m away from a cliff bangs two pieces of wood together and hears an echo 3.5 seconds later. Determine the speed of sound in air at the place.
Date posted: February 11, 2017. Answers (1)
- An observer watching a fireworks display sees the light from an explosion and hears the sound 2 seconds later(Solved)
An observer watching a fireworks display sees the light from an explosion and hears the sound 2 seconds later. How far was the explosion from the observer
Date posted: February 11, 2017. Answers (1)
- A mine worker stands between two vertical cliffs 400 m from the nearest cliff. The cliffs are x distance apart(Solved)
A mine worker stands between two vertical cliffs 400 m from the nearest cliff. The cliffs are x distance apart. Every time he strikes the rock once, he hears two echoes; the first one after 2.5s, while the second follows 2s later. From this information, calculate:
i) The speed of the sound in air
ii) The value of x.
Date posted: February 11, 2017. Answers (1)
- A ship in an ocean sends out an ultra sound whose echo is received after 3 seconds. If the wavelength of the ultra sound in water is 7.5 cm(Solved)
A ship in an ocean sends out an ultra sound whose echo is received after 3 seconds. If the wavelength of the ultra sound in water is 7.5 cm, and the frequency of the transmitter is 20 kHz,determine the depth of the ocean.
Date posted: February 11, 2017. Answers (1)
- The wavelength of a radio wave is 1 km. Determine its frequency.(Solved)
The wavelength of a radio wave is 1 km. Determine its frequency.
(Take the speed of light as 3.0 X 108ms-1)
Date posted: February 11, 2017. Answers (1)
- State difference between mechanical and electromagnetic waves(Solved)
State difference between mechanical and electromagnetic waves.
Date posted: February 11, 2017. Answers (1)
- The audible frequency range for a certain person is 30 Hz and 16, 500 Hz. Determine the largest wavelength of sound in air the person can detect(Solved)
The audible frequency range for a certain person is 30 Hz and 16, 500 Hz. Determine the largest wavelength of sound in air the person can detect.
(Speed of sound in air = 330m/s)
Date posted: February 11, 2017. Answers (1)