06:53Newton's 2nd Law (1 of 21) Calculate Acceleration w/o Friction, Net Force HorizontalStep by Step Science197views
Multiple ChoiceAn 800-kg car is traveling along a horizontal road directly towards a cliff. The driver notices and brakes, resulting in a 5,000-N net force slowing the car down. If the car's initial speed was 20 m/s and the car stops just before going over the cliff, how far away was the car from the cliff when the driver hit the brakes?1037views22rank4commentsHas a video solution.
Multiple ChoiceThe following forces are acting on a 250g box on a horizontal surface. A downward force of gravity with magnitude 2.45N. An upward normal force with magnitude 2.45N. A rightward pull from a rope of 5.0N. A leftward kinetic friction force with magnitude 7.5N. At this instant, what is the magnitude of the acceleration of the box?255views1rank
Multiple ChoiceTabletop shuffleboard is a popular pub game where players slide pucks across a tabletop trying to get them as close to the end of the table as possible, without falling off. Shuffleboard tables are typically covered in shuffleboard wax, which gives a very low coefficient of kinetic friction between the table and puck. Suppose that one particular table is 6.0 long m and has a coefficient of kinetic friction of 0.080. What speed should a player give to a puck on one end of the table so the puck just makes it to the far end?368views1comments
Textbook Question(II) A child on a sled reaches the bottom of a hill with a velocity of 10.0 m/s and travels 25.0 m along a horizontal straightaway to a stop. If the child and sled together have a mass of 60.0 kg, what is the average retarding force on the sled on the horizontal straightaway?47viewsHas a video solution.
Textbook QuestionWhen jumping straight up from a crouched position, an average person can reach a maximum height of about 60 cm. During the jump, the person's body from the knees up typically rises a distance of around 50 cm. To keep the calculations simple and yet get a reasonable result, assume that the entire body rises this much during the jump. (a) With what initial speed does the person leave the ground to reach a height of 60 cm?74viewsHas a video solution.
Textbook QuestionFIGURE EX6.10 shows the force acting on a 2.0 kg object as it moves along the x-axis. The object is at rest at the origin at t = 0s. What are its acceleration and velocity at t = 6 s?366views2rankHas a video solution.
Textbook QuestionThe forces in FIGURE EX6.9 act on a 2.0 kg object. What are the values of ax and ay, the x- and y-components of the object's acceleration? 585viewsHas a video solution.
Textbook QuestionCompressed air is used to fire a 50 g ball vertically upward from a 1.0-m-tall tube. The air exerts an upward force of 2.0 N on the ball as long as it is in the tube. How high does the ball go above the top of the tube? Neglect air resistance.240viewsHas a video solution.
Textbook QuestionA 20,000 kg rocket has a rocket motor that generates 3.0 x 10^5 N of thrust. Assume no air resistance. (a) What is the rocket's initial upward acceleration?186views1rankHas a video solution.
Textbook QuestionA horizontal rope is tied to a 50 kg box on frictionless ice. What is the tension in the rope if: (b) The box moves at a steady 5.0 m/s?333viewsHas a video solution.
Textbook Questiona. A rocket of mass m is launched straight up with thrust Fₜₕᵣᵤₛₜ. Find an expression for the rocket's speed at height h if air resistance is neglected.102viewsHas a video solution.
Textbook QuestionYour forehead can withstand a force of about 6.0 kN before fracturing, while your cheekbone can withstand only about 1.3 kN. Suppose a 140 g baseball traveling at 30 m/s strikes your head and stops in 1.5 ms. a.What is the magnitude of the force that stops the baseball?651viewsHas a video solution.
Textbook QuestionA 500 g model rocket is on a cart that is rolling to the right at a speed of . The rocket engine, when it is fired, exerts an 8.0 N vertical thrust on the rocket. Your goal is to have the rocket pass through a small horizontal hoop that is 20 m above the ground. At what horizontal distance left of the hoop should you launch?431viewsHas a video solution.
Textbook QuestionAs a science fair project, you want to launch an 800 g model rocket straight up and hit a horizontally moving target as it passes 30 m above the launch point. The rocket engine provides a constant thrust of 15.0 N. The target is approaching at a speed of 15 m/s. At what horizontal distance between the target and the rocket should you launch?176viewsHas a video solution.
Textbook QuestionTwo rock climbers, Paul and Jeanne, use safety ropes of similar length. Jeanne's rope is more elastic, called a dynamic rope by climbers. Paul has a static rope, not recommended for safety reasons.<IMAGE>(a) Jeanne (Fig. 4–72) falls freely about 2.0 m and then the rope stops her over a distance of 1.0 m. Estimate how large a force (assume constant) she will feel from the rope. (Express the result in multiples of her weight.)30viewsHas a video solution.
Textbook QuestionA 25-g projectile is fired into a cube of ballistic gel at a velocity of 360 m/s. If the projectile penetrates 15 cm into the gel before stopping, find the average force exerted by the gel onto the projectile. Use (a) kinematics and dynamics (Newton's laws) 53viewsHas a video solution.
Textbook Question(III) A particle of mass m, initially at rest at x = 0, is accelerated by a force that increases in time as F=Ct² . Determine its velocity v and position x as a function of time.59viewsHas a video solution.
Textbook Question(II) At the instant a race began, a 65-kg sprinter exerted a force of 720 N on the starting block at a 22° angle with respect to the ground.(a) What was the horizontal acceleration of the sprinter?43viewsHas a video solution.
Textbook Question(II) At the instant a race began, a 65-kg sprinter exerted a force of 720 N on the starting block at a 22° angle with respect to the ground.(b) If the force was exerted for 0.32 s, with what speed did the sprinter leave the starting block?45viewsHas a video solution.
Textbook QuestionTwo rock climbers, Paul and Jeanne, use safety ropes of similar length. Jeanne's rope is more elastic, called a dynamic rope by climbers. Paul has a static rope, not recommended for safety reasons.<IMAGE>(b) In a similar fall, Paul's rope stretches by only 30 cm. How many times his weight will the rope pull on him? Which climber is more likely to be hurt?33viewsHas a video solution.
Textbook QuestionYou are driving home in your 860-kg car at 15 m/s. At a point 45 m from the beginning of an intersection, you see a green traffic light change to yellow, which you expect will last 4.0 s, and the distance to the far side of the intersection is 65 m (Fig. 4–71). <IMAGE>(a) If you choose to accelerate, your car's engine will furnish a forward force of 1200 N. Will you make it completely through the intersection before the light turns red?32viewsHas a video solution.
Textbook QuestionSuppose a 65-kg person jumps from a height of 3.0 m down to the ground.(c) Estimate the decelerating force if the person lands stiff-legged so d ≈ 1.0 cm .<IMAGE>40viewsHas a video solution.
Textbook Question(II) The drag force on large objects such as cars, planes, and sky divers moving through air is more nearly F_D = -cv² .(a) For this quadratic dependence on v, determine a formula for the terminal velocity vτ , of a vertically falling object..30viewsHas a video solution.
Textbook Question(III) Air resistance acting on a falling body can be taken into account by the approximate relation for the acceleration: a = dv/dt = g ― kv , where k is a constant. (b) Determine an expression for the terminal velocity, which is the maximum value the velocity reaches.36viewsHas a video solution.
Textbook Question(II) A 2.0-kg purse is dropped from the top of the Leaning Tower of Pisa and falls 55 m before reaching the ground with a speed of 27m/s . What was the average force of air resistance?29viewsHas a video solution.
Textbook Question(II) The terminal velocity of a 3 x 10⁻⁵ kg raindrop is about 9 m/s. Assuming a drag force FD = -bv , determine (b) the time required for such a drop, starting from rest, to reach 63% of terminal velocity.12viewsHas a video solution.