Physics Answers

A 300g mass hangs at the end of a string. A second string hangs from the bottom of that mass and support a 900g mass. (A) find the tension in each string when the masses are accelerating upward at 0.700m/s². (b) Find the tension in each string when the masses are accelerating downward at 0.700m/s².

Just as her parachute opens, a 60-kg parachutist is falling at a speed of 50.0 m/s. After 0.80 seconds has passed, the chute is fully open and her speed has dropped to 12.0 m/s. Find the average retarding force exerted upon the chutist during this time if the deceleration is uniform.

1.    An object 0.3 cm tall is placed 15.5 cm to the left of the vertex of a concave mirror with a center of curvature of 24.0 cm. Determine the position, size, orientation and type (real or virtual) of the image.

1.    An object is 28 centimeters from the center of a silvered spherical glass Christmas tree ornament 4.0 cm in diameter. What is the focal length of the ornament? Is it a concave or convex mirror? Will the image be real or virtual? Will the image be upright or inverted? What are the position and magnification of its image? If the object is 3.0-meter-high, what is the height of the image?

A 2.5 kg object is whirled in a vertical circle whose radius is 0.89 m. If the time of one revolution is 0.94 s, the magnitude of the tension in the string (assuming uniform speed) when it is at the bottom is ___x10²N. (Give your answer with 2 sig digs, and do not include units)

A student is rotating a bucket of water in a vertical circle with a radius of 0.85m. In order for water to not spill out at the top of the swing, the bucket requires a minimum speed of ___m/s. (Give your answer with the correct number of significant digits and do no include units)

What are the horizontal range and maximum height of a bullet fired with a speed of 20 m/s at 30° above the horizontal?

A block of mass 500 g presses a spring with distance X, as shown in figure. The spring is negligible mass and has spring constant 4500 mN/m. When it is released, the block travels along a frictionless horizontal surface to point A, the bottom of frictionless circular track of radius R = 2 m and continue to move up the track. The block’s speed at point A is 12 m/s. What is X? and What is minimum X to complete the circular motion?

7, Earth has an orbital period of 365 days and its mean distance from the Su planet Pluto's mean distance from the Sun is 5.896x109 km. Using Kepler's the orbital period in Earth days.

8. The planet Venus orbits the Sun with a mean orbital radius of 1.076x101

is 1.99x1030 kg. Using Newton's version of Kepler's third law, calculate the orbital period of Venus.

On a 40-km bike ride, a cyclist rides the first 20 km at 20 km/h.If the cyclist rides very fast for the final 20 km, what is the maximum value his average speed could approach?