Question

please give me a clear explanation of Q10,Q12 and rest direct answer

Answer 1

Q10 .
first case
—————

both move towards each other
so, relative velocity = 4m/s
V + U = 4 m/s -------(1)
.
second case
————————

both moves same direction
so, relative velocity = 4/10 = 0.4 m/s
V - U = 0.4 m/s -------(2)

solve both equation ,
V = 2.2 m/sec and U = 1.8 m/s



Q12 .

formula, of magnitude of addition of two vectors is .....
R =√(R1² +R2² +2R1R2cos∅)

- 1 ≤ cos∅ ≤ 1

(a) R= √(2² +3² +2×2×3×cos∅)
4² = 4 + 9 + 12cos∅
cos∅ = 1/3 so, it's possible

(b) 4 =√(1² +3² +2×3cos∅)
cos∅ = 1 it's possible

(c) 4= √1² +5² +2×5× cos∅)
-10 = 10cos∅
cos∅ = -1 its possible

(d) 4 =√(1² +7² +2×7 cos∅)
-34 = 14cos∅
cos∅ = -2 , but cos∅ ≤ -1

so, its not possible .

Answer 2

Q10.

first case

both move towards each other so, relative velocity = 4m/s V +U= 4 m/s -------(1)

second case

both moves same direction so, relative velocity = 4/10 = 0.4 m/s V-U = 0.4 m/s ----(2)

solve both equation, V = 2.2 m/sec and U = 1.8 m/s

Q12.

Physics

15 points

formula, of magnitude of addition of two vectors is .. R=v(R12 +R22 +2R1R2cos)

-1 cos 31

(a) R= V(22 +32 +2x2x3xcos)

42 = 4 + 9 + 12cos

cos = 1/3 so, it's possible

(b) 4 = (12 +32 +2x3cos)

cos = 1 it's possible (c) 4= v12 +52 +2x5x cosØ)

-10 = 10cos

cosØ = -1 its possible

(d) 4 =v(12 +72 +2x7 cosØ) -34 = 14cos cosØ = -2 , but cosØ <-1

so, its not possible.