Get college assignment help at uniessay writers in an anniversary celebration of Marilyn bell’s 1954 feat – she was the first person to swim across lake Ontario – a swimmer set out from the shores of New york and maintained a velocity of 4 m/s [N]. as the swimmer approached the Ontario shore, she encountered a cross current of 2 m/s [E 25 S]. calculate her velocity with respect to the crowd observing from the beach (with respect to the ground)
A 87 arrow is fired from a bow whose string exerts an average force of 120N on the arrow over a distance of 78cm. What is the speed of the arrow as it leaves the bow?
A projectile is launched straight up at 101 m/s. How fast is it moving at the top of its trajectory? A cannonball launched with an initial velocity of 131 m/s at an angle of 45° follows a parabolic path and hits a balloon at the top of its trajectory. Neglecting air resistance, how fast is it going when it hits the balloon? m/s What is the acceleration of the cannonball just before it hits the balloon? m/s2
Two friends, Al and Jo, have a combined mass of 174 kg. At an ice skating rink they stand close together on skates, at rest and facing each other, with a compressed spring between them. The spring is kept from pushing them apart, because they are holding each other. When they release their arms, Al moves off in one direction at a speed of 0.911 m/s, while Jo moves off in the opposite direction at a speed of 1.20 m/s. Assuming that friction is negligible, find Al’s mass.
After falling from rest from a height of 28 m, a 0.46 kg ball rebounds upward, reaching a height of 18 m. If the contact between ball and ground lasted 1.7 ms, what average force was exerted on the ball?
A 26.0 child plays on a swing having support ropes that are 2.20 long. A friend pulls her back until the ropes are 43.0 from the vertical and releases her from rest.
The 2.8 kg, 40 cm diameter disk in the figure below is spinning at 280 rpm. How much friction force must the brake apply to the rim to bring the disk to a halt in 2.5 s?
Why do we place guards over capacitors and where does the guard voltage come into play when using an analogue L-C meter to probe the capacitance? For instance, we have an isolated spherical capacitor on an insulating rod with a conducting base. Why do you get the most accurate vale for capacitance when applying a guard voltage to the base and then probing the sphere instead of grounding the base or doing neither?
‘A speed ramp at an airport is basically a large conveyor belt on which you can stand and be moved along.’? ‘A speed ramp at an airport is basically a large conveyor belt on which you can stand and be moved along. The belt of one speed ramp moves at a constant speed such that a person who stands still on it leaves the ramp 70 s after getting on. Clifford is in a real hurry, however, and skips the speedramp. Starting from rest with an acceleration of 0.39 m/s2, he covers the same distance as the ramp does, but in one-fourth the time. What is the speed at which the belt of the ramp is moving?
A laser emits a single, 3.0-ms pulse of light that has a frequency of 2.83 × 1011 Hz and a total power of 65 000 W. How many photons are in the pulse?
Get college assignment help at uniessay writers Determine how many calories of heat must be removed to change 100g of vapor at 240°C to solid at 20°C. Consider the following properties of the substance: heat of fusion 300 cal/g, heat of vaporization 600 cal/g, specific heat capacity as a liquid -0.75 cal/g-Co, melting point at 20°C and boiling point of 240°C.
charged particle moves in a region of uniform field along a helical path (radius = 3.0 cm, pitch = 9.0 cm) as shown. What is the angle between the velocity of the particle and the magnetic field?
A stunt man whose mass is 70 kg swings from the end of a 4.5 m long rope along the arc of a vertical circle. Assuming that he starts from rest when the rope is horizontal, find the tensions in the rope that are required to make him follow his circular path at each of the following points. (a) at the beginning of his motion (b) at a height of 1.5 m above the bottom of the circular arc (c) at the bottom of the arc
When a .22-caliber rifle is fired, the expanding gas from the burning gunpowder creates a pressure behind the bullet. This pressure causes the force that pushes the bullet through the barrel. The barrel has a length of 0.60 m and an opening whose radius is 2.8 10-3 m. A bullet (mass = 2.7 10-3 kg) has a speed of 380 m/s after passing through this barrel. Ignore friction and determine the average pressure of the expanding gas. Pa
One-half mole of a monatomic ideal gas absorbs 1100 J of heat while 2400 J of work is done by the gas. (a) What is the temperature change of the gas? K (b) Is the change an increase or a decrease? increase decrease
Three moles of a monatomic ideal gas are heated at a constant volume of 2.40 m3. The amount of heat added is 4.66 103 J. (a) What is the change in the temperature of the gas? K (b) Find the change in its internal energy. J (c) Determine the change in pressure. Pa
A crate with mass 36.0 initially at rest on a warehouse floor is acted on by a net horizontal force of 142 . how far does it travel in 12s and what is its speed at that time?
A 52 kg pole vaulter running at 12 m/s vaults over the bar. Her speed when she is above the bar is 0.7 m/s. Neglect air resistance, as well as any energy absorbed by the pole, and determine her altitude as she crosses the bar.
How long does it take to do 432 joules of work with 75 watts of power?
a model rocket is lauched straight upward with an initial speed of 80.0 m/s. it accelerates with a constnat acceleration of 2.00 m/s^2 until its engines stop at an attitude of 200 m. the rocket continues move in free fall until its reaches the ground. Whatis the total time the rocket is in the air?
Bruce stands on a bank beside a pond, grasps the end of a 20.0-m-long rope attached to a nearby tree and swings out to drop into the water. If the rope starts at an angle of 35o, with the vertical, what is Bruce’s speed at the bottom of the swing?
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