Page 83 - Physics - XI

Procedure

1. First of all, connect one end of the water pipe to the water tap and insert a metallic nozzle in the other
end of the water pipe.
2. Open the water tap and check that there is no leakage of water from the pipe. Remove if it is there.
3. Place the protractor in a slot in a horizontal base to make its plane vertical and graduated surface
towards yourself.

4. Put the jet at the centre O of the protractor and make the jet pass through 15° marking on it.
5. Now, open the water tap, and adjust the tap so that water coming out of the jet would fall on the ground
at a few metre distance from the centre of the protractor O as shown in Fig. 5.1. Make a mark A on the
1
ground where the water from jet falls on the ground.
6. Change the angle of projection by fi xing the nozzle of jet along 30°, 45°, 60°, and 75° and repeat
step 5 to get points marked A , A , A , and A respectively.
2 3 4 5
7. Measure distances OA , OA , OA , OA , and OA with the help of a measuring tape. These distances
1
5
4
3
2
give range R for diff erent angles of projection.
8. Note all the observations in the table.
Observations
Least count of the measuring tape = ..... cm
Table for calculation of angle of projection and range of projectile
S. No. Angle of projection of water jet θθ (in degrees) Range of water jet R (cm)

1. 15° OA =
1
2. 30° OA =
2
3. 45° OA =
3
4. 60° OA =
4
5. 75° OA =
5
Graph Y

Plot a graph between angle of projection θ and range Scale used on:
R, taking θ along X-axis and R along Y-axis. The X-axis, 1 cm = ... degree
graph is shown in Fig. 5.2 Y-axis, 1 cm = ... cm

Result

The variation of range (R) with the angle of projection Range (R) (cm)
(θ) is shown in Fig. 5.2. It is a parabola which agrees
with theory. From the graph we can conclude that the 15° 30° 45° 60° 75° X
range is maximum for angle of projection of 45°. Angle of projection (θ) (degrees)

Precautions Fig. 5.2: Graph between angle of projection and range.

1. Water level in reservoir should remain constant to keep velocity of projection constant.
2. Jet should be thin so that a sharp point of return can be obtained.

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