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In a water-tank test involving the launching of a small model boat, the model's initial horizontal velocity is 6 m/s and its horizontal acceleration varies linearly from -12 m/s2 at
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Vector Mechanics For Engineers
- 2. A car accelerates uniformly from rest and reaches a speed of 28.0 m/s in 8.00 s. If the radius of a tire is 30 cm, find the number of revolutions the tire makes during this motion, assuming that no slipping occurs.arrow_forwardIn class, we used the 1967 gravity formula to derive the change in gravitational acceleration g with latitude, and we calculated the result at latitude o = 45°. Plot the rate of change of g with latitude () in units of mgal/km, from the equator to the pole (ø = 0° to ø = 90°). Be careful with the units; you will need to convert radians to km. (Recall that there are 27 radians in a full circle, 360°.) doarrow_forwardIn an experiment to test Newton’s second law of motion, we measure the acceleration of two masses (2 kg, and 3 kg.) which are attached to the two ends of a rope that passes over a pulley, as in an Atwood’s machine. What is the theoretical acceleration (a) if the pulley has no mass, (b) if the pulley has a mass of 0.5 kg.?arrow_forward
- An engineer in a locomotive sees a car stuck on the track at a railroad crossing in front of the train. When the engineer first sees the car, the locomotive is 330 m from the crossing and its speed is 21 m/s. If the engineer's reaction time is 0.44 s. what should be the magnitude of the mini- mum deceleration to avoid an accident? Answer in units of m/s2.arrow_forwardA worker drags a crate across a factory floor by pulling on a rope tied to the crate. The worker exerts a force of magnitude F = 200N on the rope, which is inclined at an upward angle q = 30° to the horizontal, and the floor exerts a horizontal force of magnitude f = 150N that opposes the motion. Calculate the magnitude of the acceleration (in the unit m/s2) of the crate if its mass is 100 kg." a)0.23 b)0.33 c)0.43 d)0.53arrow_forward3. A 15-kg rock is dropped from rest on the earth and reaches the ground in 1.75 s. When it is dropped from the same height on Saturn's satellite Enceladus, it reaches the ground in 18.6 s. (a) What is the acceleration due to gravity on Enceladus? (b) How long will it take for the rock to reach the ground on Earth if it was released 100 m above the Earth's surface? (c) Same question in (b) but in Enceladus.arrow_forward
- A motorist traveling at a constant 15 m/s (54 km/h, or about 34 mi/h) passes a school crossing where the speed limit is 10 m/s (36 km/h, or about 22 mi/h). Just as the motorist passes the school-crossing sign, a police officer on a motorcycle stopped there starts in pursuit with constant acceleration 3.0 m/s2 . (a) How much time elapses before the officer passes the motorist? At that time, (b) what is the officer’s speed and (c) how far has each vehicle traveled?arrow_forwardYou place a 0.18-kg sonic ranger on a low-friction track in front of a 0.50-kg cart to measure the cart's velocity in the Earth reference frame, which turns out to be +(1.0 m/s). You are distracted, the cart hits the ranger in a totally inelastic collision, and the two objects then move forward together. A friend is running toward the cart with a velocity of -(3.5 m/s) with her sonic ranger on and pointed at the cart. ▾ Part A What is the x-component of the momentum of the cart with the ranger stuck to it, in your friend's reference frame?arrow_forwardA 3.1 kg object is initially at rest and is experiencing a net force of magnitude 4.7e^-t/2 N. As time approaches infinity, notice that the net force decays toward 0 N, which tells us that the acceleration is also dropping to 0 m/s^2 (and so the velocity is leveling off to a terminal speed). What is the terminal speed? (Ans.= 3.0 m/s)arrow_forward
- You drop a golf ball from a height of 1 m above the ground. It hits the ground and returns to a height of 0.5 m. Your friend makes the following argument: “The impulse Earth imparts to the golf ball as it falls must be larger than the impulse the ground imparts when the ball bounces because the time interval over which Earth exerts a force on the ball is much larger than the time interval over which the ground exerts a force on the ball.” Draw one or more momentum bar charts and use them to explain either your friend is right or wrong.arrow_forwardAs shown below, a rock rests on a platform and is connected to a pickup by a cable. The pickup has a constant forward acceleration. The rock, B, weighs 1000 lb and the platform, A, weighs 200 Ib. Which of the following is a true statement? A O The cable tension is 200 lb. O The cable tension is 1200 lb. O The cable tension is more than 1200 lb. O The cable tension is less than 1200 lb.arrow_forwardQ.1: For the figure below, knowing that the angle 0 = 60° and µ = 0.6 at points A and B, (a):the value of acceleration at location A is equal to: B O 5.55 m/s2 O - 5.23 m/s2 5.85 m/s2 -6.1 m/s2 O -5.55 m/s2arrow_forward
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