Answer:
t_a = 7 s
t_w = 5 s
Step-by-step explanation:
Given:
- The average speed in air v_a = 16 m/s
- The average speed in water v_w = 3 m/s
- The total distance D = 127 m
- The total time T = 12 s
Find:
How long did the stone fall in air and how long did it fall in the water?
Solution:
- Lets time taken by stone to drop through air as t_a = t_a.
- The time taken in water would be t_w = (12 - t_a)
- The total distance covered can be calculated as:
D = v_a*t_a+ v_w*(12 - t_a)
127 = 16*t_a + 3*(12 - t_a)
Simplify and solve for t:
91 = 16*t_a - 3t_a
13*t_a = 91
t_a = 7 s
t_w = 5 s
Answer:
Step-by-step explanation:
Pythagorean theorem,
hypotenuse² = Base² + altitude²
= 8² + 10²
= 64 + 100
= 164
hypotenuse = √164 = 12.8 cm
Answer: Approximately 72.69 meters
Step-by-step explanation:
Answer:
Step-by-step explanation:
Hint: 1- 2sin²x = Cos 2x
LHS = 1 - 2Sin² (π/4 - Ф/2)
= Cos 2 *(π/4 - Ф/2)
= Cos 2*π/4 - 2*Ф/2
= Cos π/2 - Ф
= Sin Ф = RHS
