Answer:
a) t = 1.6 s
b) d = 4.9 m
c) v = 16 m/s
d) θ = 79°
Explanation:
time of fall
t = √(2h/g) = √(2(12)/9.8) = 1.5649... s
d = vt = 3.1(1.56) = 4.8512...
vertical velocity vy = at = 9.8(1.56) = 15.336... m/s
v = √(15.336² + 3.1²) = 15.6464... m/s
θ = arctan(15.336/3.1) = 78.5724...°
Speed
= (distance covered) / (time to cover the distance)
= (25 m) / (5.0 sec) = 5.0 m/s .
Since car is initially at rest so at that position the net force on car in vertical as well as horizontal both direction is zero
but after lights are green the car will speed up in horizontal direction
so now we can say that
It will accelerate in horizontal direction
So now as per Newton's formula we have

so now the force in horizontal direction will become nonzero while in vertical direction car is still in equilibrium
So now we can say


so the correct answer will be
C. The net force on the car is greater than zero in the horizontal direction.
Answer:
1 , 2 and , 4 on usa test prep
Explanation: