On a day that the temperature is 20. 0"�, a concrete walk is poured in such a way that the ends of the walk are unable to move. Take Young’s modulus for concrete to be 7.00 × 102 �/m2 and the compressive strength to be 2.00x109 N/m2 . (a) What is the stress in the cement on a hot day of 50. 0"�? (b) Does the concrete fracture? (4%)

1. explain how you calculate the net force in any direction on the box. 2. suppose an upward force of 15n is added to the box. what will be the net vertical force on the box? 3. what force could be applied to the box to make the net force in the horizontal direction zero? explain. 4. suppose a force of 25n to the right is added to the box. what will be the net force to the right?