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A javelin thrower standing at rest holds the center of the javelin behind her head, then accelerates it through a distance of 70 cm as she throws. She releases the javelin 2.0 m above the ground traveling at an angle of 300 above the horizontal. Top-rated javelin throwers do throw at about a 30° angle, not the 45° you might have expected. because the biomechanics of the arm allow them to throw the javelin much faster at 30° than they would be able to at 45°. In this throw, the javelin hits the ground 62 m away. What was the acceleration of the javelin during the throw? Assume that it has a constant acceleration.
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Physics for Scientists and Engineers: A Strategic Approach, Vol. 1 (Chs 1-21) (4th Edition)
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- A javelin thrower standing at rest holds the center of the javelin behind her head, then accelerates it through a distance of 70 cm as she throws. She releases the javelin 2.0 m above the ground traveling at an angle of 30 degrees above the horizontal. Top-rated javelin throwers do throw at about a 30 degree angle, not the 45 degree you might have expected, because the biomechanics of the arm allow them to throw the javelin much faster at 30 degrees than they would be able to at 45 degrees . In this throw, the javelin hits the ground 64 m away. What was the acceleration of the javelin during the throw? Assume that it has a constant acceleration.arrow_forwardIf the car's speed were not reduced by any structural effects or by friction, how long would it take to complete the race? What is the speed of the car at the end of the race?arrow_forwardA basketball is thrown at 45° to the horizontal. The hoop is located 3.6 m away horizontally at a height of 1.2 m above the point of release. What is the required initial speed? m/sarrow_forward
- A physics student stands on a cliff overlooking a lake and decides to throw a softball to her friends in the water below. She throws the softball with a velocity of 24.5 m/s at an angle of 31.5° above the horizontal. When the softball leaves her hand, it is 12.5 m above the water. How far does the softball travel horizontally before it hits the water? Neglect any effects of air resistance when calculating the answer. Macmillan Learning horizontal distance: Earrow_forwardA volcano erupted and spit a rock in the atmosphere at an angle of 35 degrees with the horizontal with an initial velocity of 25m/s. The rock hit the ground 20 meters below the crater. What is the direction of the rock in degrees before hitting the ground? O 50 60 O 40 O o o Oarrow_forwardTwo friends are playing catch. They both are about the same height so the release height of the ball when thrown and the height of the catch are both 1.75 meters above the ground. The friend on the right throws the ball at a speed of 15 m/s at an angle of 33° above the horizontal. Assume you can ignore air resistance for this problem. (1) What are the horizontal and vertical components of the initial velocity of the ball? (2) How far away should the second friend stand to catch the ball (at a height of 1.75 m above the ground)? 1: You'll first need to solve for the time the ball is in the air. 2: If you don't know how to solve for time, then pick a value for the time the ball is in the air and perform your remaining calculations using that value for timearrow_forward
- Lili throws a ball to her friend Eric. The ball leaves Lili's hand a distance 2.00 meters above the ground with an initial speed of 18.0 m/s at an angle 30.0° with respect to the horizontal. Eric catches the ball 1.20 meters above the ground. What is the distance between Lili and Eric, in meters? Use g = 10.0 m/s2.arrow_forwardAn airplane is dropping bales of hay to cattle stranded in a blizzard on the Great Plains. The pilot releases the bales at 150 m above the level ground when the plane is flying at 75 m>s in a direction 55° above the horizontal. How far in front of the cattle should the pilot release the hay so that the bales land at the point where the cattle are stranded?arrow_forwardA boy is playing flying fox over a swimming pool as illustrated in the figure. A cable mounted on the top of a tall tower runs down to the ground with an angle = 26° with respect to the horizontal. The boy at the top of the tower grabs a pulley on the cable and slides down from rest. His initial height was ho 15 m above the water. When he reaches hi above the water, he releases his hands from the pulley and falls into the water. The boy is subject to the regular force of gravity (g-9.80665 m/s2). Ignore friction and air resistance. <=10m (a) Determine the speed of the boy at the moment he releases his hands from the pulley. Answer: 9.90 m/s (b) Determine the speed of the boy at the moment he splashes into the water. Answer: 17 (c) At what angle with respect to the horizontal does the boy enter the water? Answer: 57.85 degreesarrow_forward
- To celebrate her good performance on a physics test, Alice decides to break out a bottle of champagne. In order to avoid property damage, she takes the bottle outside to uncork it. The cork pops off the champagne bottle with a velocity of 12.0 m/s at an angle of 15° relative to the vertical. When the cork is released, Alice is holding the bottle such that the cork is 1.80 m above the ground. How far does Alice have to walk to retrieve the cork?arrow_forwardIn the Marvel comic series X-Men, Colossus would sometimes throw Wolverine toward an enemy in what was called a fastball special. Suppose Colossus throws Wolverine at an angle of 0 = 23.0° with respect to the ground (see figure below). Wolverine is d = 2.14 m above the ground when he is released, and he leaves Colossus's hands with a speed of v; = 22.6 m/s. d (a) Using conservation of energy and the components of the initial velocity, find the maximum height attained by Wolverine during the flight. m (b) Using conservation of energy, what is Wolverine's speed the instant before he hits the ground? m/sarrow_forwardNathan Hunt is faced with the following problem in one of his impossible missions. A briefcase full of secret documents is just thrown from the top of a building with an initial speed vpo = 5 m/s at an angle 0 from the vertical. Hunt is on the next building. As soon as the briefcase is thrown, he leaves the roof of the building horizontally with an initial speed vy0. VB,0 H VH,0 Relevant quantities: e = 37°, H = 8 m and D = 11 m. (a) If Hunt wants to catch the briefcase, with which initial speed he should leave the rooftop? VH,0= (b) How long will it take Hunt to catch the briefcase? t =arrow_forward
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