Question

10. Numerical problems:

b. A stone is thrown vertically upwards with an initial velocity of 20 m/sec.find the maximum height it reaches and the time taken by it to reach the height. (g = 10 m/s2).

c. A car is moving at a rate of 72 km/hr. How far does the car move when it stops after 4 seconds?

d. A bus starts from rest. If the acceleration is 2 m/s2, find
1. the distance travelled.
2. the velocity after 2 seconds.

e. A stone is thrown vertically upward with the velocity of 25 m/s. How longo it take to reach the maximum height? Also calculate the height.


with process please ​

Answer 1

a)20 m,2s

Step-by-step explanation:

Given

Initial velocity=20 m /sec

g=10 m/s square

v =0m/s

h =?

t =?

now,

v = U +gt

=v=20 +10t

Or,10t=20

Or,t=20

10

therfore ,2 s.

Again,

h=ut -1 gt square

2

Or, h=20×2-1×10(2)square (multiply and cut )2×5 =10

; 2

Or,40-5×4

therefore , 20m

Answer 2

For question e,

u = 25 ms-1
v = 0 m/s
a = -10m/s^2

We have to find time and distance,

For time,

v = u + at

Which can be rephrased as,

v - u/a = t

t = 0 - 25 / -10

t = 2.5 secs

Hence, the stone takes 2.5 secs to reach the maximum height.

To calculate the maximum height attained by the stone, we have to calculate distance/ displacement .

The formula for calculating distance is,

s = ut + 1/2at^2

s = 25 * 2.5 + 1/2 * -10 * 2.5 * 2.5

s = 62.5 + (- 31.25)

s = 62.5 - 31.25

s = 31.25mts

Hence, the maximum distance travelled by the stone is 31.25 meters.

Hope this helps you. Plz let me know if you have any doubts.