A 350-g air track cart on a horizontal air track is attached to a string that goes over a frictionless pulley with a moment of inertia of 6.00 × 10-6 kg ∙ m2 and a radius of 1.35 cm. If the string is pulled vertically downward by a force of 2.50 N,
(a) what is the magnitude of the acceleration of the cart?
(b) what is the tension in the horizontal string between the pulley and the cart?