Amanda and Bertha are in a car race. Their cars have the same mass. At one point in the race, they both change their speeds by 10 m/s in 2 seconds. Ignore air friction. 2 s later 2s later 10 m/s 20 m/s 20 m/s 30 m/s Amanda Bertha

A 31.0-kg skateboarder rides on a 10.0-kg skateboard at 5.7 m/s on a level road before jumping into air with a speed of 10.0 m/s against the ground in the direction of 27.0◦ above the forward, horizontal direction to leave the skateboard. Ignore air resistance and the friction between the road and skateboard.   What is the maximum height that the skateboarder can reach? (A) 1.05 m; (B) 1.25 m; (C) 1.45 m; (D) 1.65 m; (E) 1.85 m.   What is the speed of the skateboard on the ground after the jump? (A) 3.85 m/s; (B) 4.05 m/s; (C) 4.25 m/s; (D) 4.45 m/s; (E) 4.65 m/s.   What is the minimum work done by the skateboarder to make the jump? (A) 994J; (B) 974J; (C) 954J; (D) 934J; (E) 914J.

Questions 4 through 6 pertain to the situation described below: A 31.0-kg skateboarder rides on a 10.0-kg skateboard at 5.7 m/s on a level road before jumping into air with a speed of 10.0 m/s against the ground in the direction of 27.0° above the forward, horizontal direction to leave the skateboard. Ignore air resistance and the friction between the road and skateboard. (4) What is the maximum height that the skateboarder can reach? (A) 1.05 m; (B) 1.25 m; (C) 1.45 m; (D) 1.65 m; (E) 1.85 m. (5) What is the speed of the skateboard on the ground after the jump? (A) 3.85 m/s; (B) 4.05 m/s; (C) 4.25 m/s; (D) 4.45 m/s; (E) 4.65 m/s. (6) What is the minimum work done by the skateboarder to make the jump? (A) 994 J; (B) 974 J; (C) 954 J; (D) 934 J; (E) 914 J.

A car of mass 1670kg initially at a speed of 80 km/m crushes into a wall, if the accident lasted for 0.2 sec. what is the amount of force exerted in the car during the crash

An arrow hits a tree penetrating 10 cm as it is brought to rest from its initial speed of 50 m/s inside the tree. The arrows mass was 50 g. a) what average force did the tree exert on the arrow to bring it to rest? 

A force of F=x^2 in Newtons acts on an object of mass m= 2 kg. If the object is at rest at x= 0 when the force F begins to act on it, what is the object’s speed at the position x= 3 m? A) 3 m/s B) 6 m/s C) 9 m/s D) 27 m/s

The mass of a pigeon hawk is twice that of the pigeons it hunts. Suppose a pigeon is gliding north at a speed of ?P=18.2 m/svP=18.2 m/s when a hawk swoops down, grabs the pigeon, and flies off, as shown in the figure. The hawk was flying north at a speed of ?H=33.1 m/s,vH=33.1 m/s, at an angle ?=45∘θ=45∘ below the horizontal at the instant of the attack. What is the birds' final speed ?fvf just after the attack?   ?f=vf=   m/sm/s What is the angle ?fθf below the horizontal of the final velocity vector of the birds just after the attack? ?f=θf=   ∘

Please please answer both questions. I will really really upvote. Thanks

10. A child begins to slide down from the top of a frictionless semi circular mound of ice of radius 5m. At what height above the ground will the child loose contact with the ice?

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