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A driver uniformly accelerates his car such that
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Chapter 2 Solutions
Physics for Scientists and Engineers: Foundations and Connections
- An object moves with constant acceleration 4.00 m/s2 and over a lime interval reaches a final velocity of 12.0 m/s. (a) If its initial velocity is 6.00 m/s, what is its displacement during the time interval? (b) What is the distance it travels during this interval? (c) If its initial velocity is -6.00 m/s, what is its displacement during points, (d) Does the change in speed of the downward-moving rock agree with the magnitude of the speed change of the rock moving upward between the same elevations? (e) Explain physically why it does or does not agree.arrow_forwardThe froghopper Philaenus spumarius is supposedly the best jumper in the animal kingdom. To start a jump, this insect can accelerate at 4.00 km/s2 over a distance of 2.00 mm as it straightens its specially adapted jumping legs. Assume the acceleration is constant. (a) Find the upward velocity with which the insect takes off. (b) In what time interval does it reach this velocity? (c) How high would the insect jump if air resistance were negligible? The actual height it reaches is about 70 cm, so air resistance must be a noticeable force on the leaping froghopper.arrow_forwardPhysics Review A hockey player strikes a puck, giving it an initial velocity of 10.0 m/s in the positive x-direction. The puck slows uniformly to 6.00 m/s when it has traveled 40.0 m. (a) What is the pucks acceleration? (b) At what velocity is it traveling after 2.00 s? (c) How long does it take to travel 40.0 m? (See Section 2.5.)arrow_forward
- An object moves with constant acceleration 4.00 m/s2 and over a time interval reaches a final velocity of 12.0 m/s. (a) If its original velocity is 6.00m/s, what is its displacement during the time interval? (b) What is the distance it travels during this interval? (c) If its original velocity is 6.00 m/s, what is its displacement during this interval? (d) What is the total distance it travels during the interval in part (c)?arrow_forwardA truck on a straight road starts from rest, accelerating at 2.00 m/s2 until it reaches a speed of 20.0 m/s. Then the truck travels for 20.0 s at constant speed until the brakes are applied, stopping the truck in a uniform manner in an additional 5.00 s. (a) How long is the truck in motion? (b) What is the average velocity of the truck for the motion described?arrow_forwardA person walks first at a constant speed of 5.00 m/s along a straight line from point to point and then back along the line from to at a constant speed of 3.00 m/s. (a) What is her average speed over the entire trip? (b) What is her average velocity over the entire trip?arrow_forward
- A paratrooper is initially falling downward at a speed of 30.6 m/s before her parachute opens. When it opens, she experiences an upward instantaneous acceleration of 82 m/s2. (a) If this acceleration remained constant, how much time would be required to reduce the paratrooper's speed to a safe 4.65 m/s? (Actually the acceleration is not constant in this case, but the equations of constant acceleration provide an easy estimate.) (b) How far does he fall in this timearrow_forwardAn object moving with uniform acceleration has a velocity of 11.0 cm/s in the positive x-direction when its x-coordinate is 3.06 cm. If its x-coordinate 2.15 s later is −5.00 cm, what is its acceleration? _____cm/s2 A ball is thrown directly downward with an initial speed of 7.45 m/s, from a height of 30.3 m. After what time interval does it strike the ground? _______s A small mailbag is released from a helicopter that is descending steadily at 2.78 m/s. (a) After 3.00 s, what is the speed of the mailbag? v = ______m/s (b) How far is it below the helicopter? d = ______m (c) What are your answers to parts (a) and (b) if the helicopter is rising steadily at 2.78 m/s? v=______m/s d=______m A model rocket is launched straight upward with an initial speed of 44.0 m/s. It accelerates with a constant upward acceleration of 1.00 m/s2 until its engines stop at an altitude of 200 m. (a) What can you say about the motion of the rocket after its engines stop? (b) What is the maximum height…arrow_forwardBetween t = 0 and t = t0, a rocket moves straight upward with an acceleration given by a(t) = A − Bt1 /2 , where A and B are constants. (a) If x is in meters and t is in seconds, what are the units of A and B? (b) If the rocket starts from rest, how does the velocity vary between t = 0 and t = t0? (c) If its initial position is zero, what is the rocket’s position as a function of time during this same time interval?arrow_forward
- The particle is moving along a straight path such that its velocity at any time t is given by v = 24t-6t^2 where v is in m/s. (a) what is the average velocity from t= 1 s to = 3 s? (b) what is the acceleration at t = 3s? (c) what is the average acceleration from t = 1s to t = 3 sec? (d) when does the particle change its direction of motion? (e) what is the distance covered from t= 1s to t= 5sarrow_forwardA crate slides across a frictionless horizontal surface with constant acceleration 4.45 m/s2 and over a time interval reaches a final velocity of 13.8 m/s. (a) If its initial velocity is 6.90 m/s, what is its displacement (in m) during the time interval? (Indicate the direction with the sign of your answer.) m (b) What is the distance it travels (in m) during this interval? m (c) If its initial velocity is −6.90 m/s, what is its displacement (in m) during the time interval? (Indicate the direction with the sign of your answer.) m (d) What is the total distance it travels (in m) during the interval in part (c)? marrow_forwardA car starts from rest and travels for 5.0 s with a uniform acceleration of +1.5 m/s 2. The driver then applies the brakes, causing a uniform acceleration of −2.0 m/s 2. If the brakes are applied for 3.0 s, (a) how fast is the car going at the end of the braking period, and (b) how far has the car gone?arrow_forward
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