Question

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4. A 1200.0 kg elevator is resting on the bottom floor and is being pulled upward by a cable (but is not moving). If the tension in the cable is 5240 N, what is the magnitude of the normal force acting on the elevator? a. 5240 N b. 4040 N с, 6520 N d. 11800 N 15. How much momentum does a 25 kg child have that is moving at 1 km/h? a. 174 kg m/s b. 6.94 kg'm/s C, 25.0 kg.m/s d. 12.5 kg m/s 16. A 5.40 kg block is placed on a ramp which is inclined at 32.0°, and begins sliding down. The coefficient of friction between the ramp and the block is 0.230. What is the magnitude of the block's acceleration? a. 3.28 m/s2 b. 1.91 m/s2 C. 7.10 m/s2 d. 5.19 m/s2 17. The force of gravity between two 5.00 kg objects is 5.70 x10-7 N. What is the distance between these objects? a. 2.42 m b. 0.0541 m c. 0.0242 m d. 5.41 m 18. A coin is thrown vertically upward with velocity 24.5 m/s at the edge of a cliff having a height of 24.0 m. With what speed does the coin hit the ground? a. 32.7 m/s b. 0 m/s c. 26.5 m/s d. 38.4 m/s

Answer 1

Momentum P = mv Given m = 25 kg, v = 1 km/h km = 1000 m P = 25 times 1000/60 times 60 kg m/s p = 6.94 kg m/s (16) Magnitude of the Block's acceleration Formula a = mg sin theta - mu_k mg cos theta/m a = g[sin theta - mu_k cos theta] mu_k - coefficient of friction a = 9.8[sin 32 degree - 0.23 times cos 32 degree] m/s^2 a = 9.8[0.529919 - 0.23 times 0.84804] m/s62 a = 9.8[0.529919 - 0.195051] m/s^2 a = 9.8[0.334868] m/s^2 a = 3.28 m/s^2 \r\n Formula g = Gm/r^2 Given g = 5.70 times 10^-7 N, m = 5 kg, G = 6.6742 times 10^-11 Nm^2/g^2 r^2 = Gm/g r^2 = 6.6742 times 10^-11 times 5/5.70 times 10^-7 r = 2.42 m