Here you need to draw a force system.
The car is the center and you have mainly two forces: velocity and gravity.
The angle they ask you for is the same angle formed by the velocity (mass* acceleration) and the gravity (mass*gravity)
And to know the angle you need to do the tangent.
Tg∡=[tex]\frac{m*3m/s^{2} }{m*9.81m/s2}[/tex]
Both masses canceld and
Tg∡=[tex]\frac{3m/s^{2} }{9.81m/s2}[/tex]
∡=arcTg 0.30
∡=187.35°
Answer:
The string make with the vertical an angle of 17.8°
Explanation:
The ball will move backwards until the horizontal component of its weight is accelerating it by 3 m/(s^2).
The horizontal component of its weight is calculated as follows
m*g*sinθ
The acceleration of the car is
m*a
a is the acceleration of the car (3 m/(s^2)), m is the mass of the ball, g is the gravitational acceleration (9. 81 m/(s^2)), and θ is the angle between the string and the vertical.
Notice that the ball doesn't swing, so the forces are at equilibrium, then:
m*g*sinθ = m*a
θ = arcsin(a/g)
θ = arcsin(3/9.81)
θ =  17.8 °
