5.Block A, with mass ma, is initially at rest on a horizontal floor. Block B, with mass mb, is initially at rest on the horizontal top surface of A. The coefficient of static friction between the two blocks is Hh- Block A is pulled with a horizontal force It begins to slide out from under B if the force is greater than:
(A)mAg
(B) mBg
(C) u smig
(D)usmBg
(E)us(mA+mB)g

1.An object starts from rest at the origin and moves along the x axis with a constant acceleration of 4 m/s2. Its average velocity as it goes from x = 2 m to x = 8 m is: (A) 1 m/s (B)2m/s(C)3m/s (D) 5m/s (E) 6 m/s

2.A ball is thrown horizontally from the top of a 20-m high hill. It strikes the ground at an angle of ㆍ450. With what speed was it thrown? Use g = 10 m/s2.  (A) 14m/s (B) 20m/s (C) 28 m/s (D) 32 m/s(E) 40 m/s

3.The speed of a particle moving in a circle 2.0 m in radius increases at the constant rate of 6.0 m/s. At an instant when the magnitude of the total acceleration is 10.0 m/s, what is the speed of the particle?(A)3.0 m/s(B)4.0 m/s (C) 5.0 ml/s (D)6.0 m/s(E)8.0 m/s

4.Block A, with a mass of 10 kg, rests on a 30* incline. The coefficient of kinetic friction is 0.20. The attached string is parallel to the incline and passes over a massless, frictionless pulley at the top. Block B, with a mass of 8.0 kg, is attached to the dangling end of the string (take √3 1.7 and g =10 m/s2). The acceleration of B is: (A) 0.72 m/s2, up (B) 0.72 m/s2, down (C) 2.6 m/s2, , up (D) 2.6 m/s2, down (E) 0 m/s2

6.As a 2.0-kg object moves from m, the constant resultant force acting on it is equal to N. If the speed of the object at the initial position is 4.0 m/s, what is its kinetio energy at its final position? (A)62 J (B)53J (C)73J (D)86J (E)24 J

7.A certain pendulum consists of a 1.5-kg mass swinging at the end of a string (length = 2.0 m). At the lowest point in the swing the tension in the string is equal to 20 N. To what maximum height above this lowest point will the mass rise during its oscillation? Take g = 10 m/s2 (A)77 cm (B)50 cm (C)63 cm (D)33 cm (E)95cm

8. A 10-g bullet moving horizontally with a speed of 2.0 km/s strikes and passes through a 4.0-kg block moving with a speed of 4.0 m/s in the opposite direction on a horizontal frictionless surface. If the block is brought to rest by the collision, what is the kinetic energy of the bullet as it emerges from the block? (A)0.51 kJ (B) 0.29kJ (C) 0.80 kJ(D) 0.13 kJ(E) 20.0 kJ

9. A wheel of radius R is mounted on a frictionless, horizontal axle that is perpendicular to the wheel and passes through the center of mass of the wheel. A light cord wrapped around the wheel supports a object of mass m. If released from rest with the string taut, the object is observed to fall with a downward acceleration of 4.0 m/s2. If the moment of inertia (of the wheel) about the given axle is written as BmR2, then B=? Take g= 10 m/s. (A)1.0 (B)1.5 (C)2.0 (D)3.0 (E) 3.5

10. A merry-go-round of radius R = 2.0 m has a moment of inertia I = 250 kg-m2, and is rotating at 10 rpm. A child whose mass is 25 kg jumps onto the edge of the merry-go-round, heading directly toward the center at 6.0 m/s. The new angular speed (in rpm) of the merry-go-round is approximately (A)10(B)9.2 (C) 8.5 (D)7.1 (E)6.4

11. The figure shows a uniform rod (length L = 1.0 m, mass m = 2.0 kg) suspended from a pivot a distance d = 0.25 m above its center of mass. If the angular frequency for small oscillations is ω, then ω2 , in (rad/s)2, is approximately (Given the moment of inertia about a perpendicular axis through the center of mass is = mL2 /12 and take g = 10 m/s2) (A)1.0 (B)6.25 (C) 2.25 (D) 17.1 (E) 12.25