Question

ans this phys question wid proper explanation

Answer 1

the initial velocity is give as vi = 3i + 4j
the acceleration is a = 0.4i + 0.3j
and the time elapsed is t = 10s
now final velocity after 10s is vf = (3i+4j)m/s + 10s(0.4i+0.3j)m/s
vf = 7i + 7j
now speed is v =7 root 2

Answer 2

Initial velocity, u = 3i + 4j
Acceleration, a = 0.4i + 0.3j
Final velocity, v = ?

We know that v = u+at

Or v = (3i + 4j) + (0.4i + 0.3j)×10

Or v = (3i + 4j) + (0.4×10)i + (0.3×10)j

Or v = (3i + 4j) + (4i + 3j)

Or v = 3i + 4i + 4j + 3j

Or v = 7i + 7j

So velocity after 10s is (7i + 7j)

Speed =|v| = √(7^2 + 7^2) = √98 = 7√2 units

Answer is b) 7√2 units