Question

प्रन
योग मिली
4.81

+5.3​

Answer 1

Step-by-step explanation:

Projectile motion is a form of motion experienced by an object or particle (a projectile) that is projected near the Earth's surface and moves along a curved path under the action of gravity only (in particular, the effects of air resistance are assumed to be negligible). This curved path was shown by Galileo to be a parabola, but may also be a line in the special case when it is thrown directly upwards. The study of such motions is called ballistics, and such a trajectory is a ballistic trajectory. The only force of significance that acts on the object is gravity, which acts downward, thus imparting to the object a downward acceleration. Because of the object's inertia, no external horizontal force is needed to maintain the horizontal velocity component of the object.

Answer 2

Step-by-step explanation:

Given :

A boy runs for 10 min at a uniform speed of 9km/hr and 20 min at average speed of 12km/hr

To Find :

Speed the boy will take in next 20 min = ?

Solution :

We know,

\sf{}Average\ Speed=\dfrac{Total\ Distance}{Total\ Time}Average Speed=Total TimeTotal Distance

Total time => 10 + 20 = 30min

Convert minute into hour.         [1h= 60min,so 1min = 1/60h]

Thus, total time in min = 30/60

\sf{}\implies 12=\dfrac{Toatl\ distance}{\frac{30}{60}}⟹12=6030Toatl distance

\sf{}\implies 12\times \dfrac{30}{60}=Total\ distance⟹12×6030=Total distance

\sf{}\therefore Total\ distance=6km∴Total distance=6km

Therefore,total distance is equal 6m

Distance covered in 10min/distance which boy walk earlier) :-

We know,

\sf{}Speed=\dfrac{Distance}{Time}Speed=TimeDistance

Covert 10 min into hr

=> 10/60hour

\sf{}\implies 9=\dfrac{Distance}{\frac{10}{60}}⟹9=6010Distance

\sf{}\implies 9\times \dfrac{10}{60}=Distance⟹9×6010=Distance

\sf{}Distance=1.5kmDistance=1.5km

Then remaining distance,

\sf{}\bf{}Remaing\ distance=Total\ distance-distance\ travelled\ earlierRemaing distance=Total distance−distance travelled earlier

\sf{}\implies 6-1.5⟹6−1.5

\sf{}\therefore 4.5km∴4.5km

Therefore,for next 20 the boy should run with a speed,

\sf{}Speed=\dfrac{Distance}{Time}Speed=TimeDistance

Covert 20min into hr

=> 20/60hr

\sf{}Speed=\dfrac{4.5}{\frac{20}{60}}Speed=60204.5

\sf{}\implies \dfrac{4.5}{\frac{2}{6}}⟹624.5

\sf{}\implies \dfrac{4.5}{\frac{1}{3}}⟹314.5

\sf{}\implies 4.5\div \dfrac{1}{3}⟹4.5÷31

\sf{}\implies 4.5\ \times 3⟹4.5 ×3

\sf{}\therefore 13.5km/h∴13.5km/h

Therefore,speed needed for next 20min is equal to 13.km/h