A 15.0 m uniform ladder weighing 500 n rests against a frictionless wall. the stair forms an angle of 60.0 ° with the horizontal. (a) find the horizontal and vertical forces exerted by the ground on the base of the ladder when an 800 n firefighter is 4.00 m from the bottom. (b) if the ladder is about to slip when the firefighter is 9.00 m above, what is the coefficient of static friction between the ladder and the ground?

11. you want to calculate the displacement of an object thrown over a bridge. using -10 m/s2 for acceleration due to gravity, what would be the total displacement of the object if it took 8 seconds before hitting the water?

Look at the potential energy diagram for a chemical reaction. which statement correctly describes the energy changes that occur in the forward reaction?

The temperature in gavin's oven is a sinusoidal function of time. gavin sets his oven so that it has a maximum temperature of 280°f and a minimum temperature of 240°. once the temperature hits 280°, it takes 20 minutes before it is 280° again. gavin's cake needs to be in the oven for 30 minutes at temperatures at or above 270°. he puts the cake into the oven when it is at 260° and rising. how long will gavin need to leave the cake in the oven? (round your answer to the nearest minute.)