Help please and explain

1. A frog jumps vertically to a height of 0.3m. What was its initial vertical velocity right as It leaves the ground? (Hint: You can find the answer to this problem using conservation of mechanical energy DR using the work energy theorem. Be sure to explain which method you are using and show your work.) . Suppose a shark of mass 2,300kg propels itself through the water with a forward thrust of 7100N, resisted by an average drag force of 4200N. (a] What is the net horizontal force on the shark? (b) What is the net work performed on the shark if it undergoes a horizontal displacement of 30m? Recall: Whee = Freed cos B. (c) If the shark has an initial velocity of vy = 12"/, use the work- energy theorem to determine the shark's final velocity after the 30m displacement described in part (b]. Fun fact: The microstructure of shark skin has toothlike bumps called "riblets" that alter the drag force. https://rovalsocietypublishing.nme/doi/pdf/10.10198/rata.2010.0201 3. Calculate the average force a 60.0-kg sprinter exerts backward on the track to accelerate from 2.00m/s to 7.50 m/s in a distance of 25.0 m, If she encounters a headwind that exerts an average force of 30.0 N against her. (Hint 1: You will need to set up a free body diagram showing off forces acting on the sprinter. Use this to find the net force, to apply the work-energy theorem. Hint 2: Newton's 3od Low tells us that if she pushes backward on the road, the road pushes forward on her with an equal and opposite force.) 4. You are driving at 30m/'s and hit your brakes, skidding to a stop. The coefficient of kinetic friction between your tires and the road is wr =0.6. The mass of your car is 1500kg. a. What is your initial kinetic energy right before you hit the brakes? b. What is the magnitude of the kinetic friction force acting on the car as it slides? [Review Ch. 5.1 from fall quarter in online text]- Does the friction do positive or negative work on the car? Explain your reasoning. d. Use the work-energy theorem to calculate how far you will skid before stopping