Mindblown: a blog about philosophy.
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Same Momentum
At what speed do a bicycle and its rider, with a combined mass of 100 kg, have the same momentum as a1300 kg car traveling at 6.0 m/s? Known variables: (mass of bicycle) m1= 100 kg (mass of car) m2= 1300kg (velocity of car) v2 = 6.0 m/s Momentum is mass x velocity. => m1 x v1 = m2…
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What Impulse was Applied?
A 57 g tennis ball is served at 45 m/s. If the ball started from rest, what impulse was applied to the ball by the racket? Known Variables: mass(m) : 57g or .057 kg velocity(v) : 45 m/s Impulse is force and time I = F x t We know that F= ma & a=v/t this would be derived F= m (v/t) Since we…
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What is the Magnitude of the Impulse Delivered?
In a Little League baseball game, the 145 g ball enters the strike zone with a speed of 15.0 m/s. The batter hits the ball, and it leaves his bat with a speed of 20.0 m/s in exactly the opposite direction. 1) What is the magnitude of the impulse delivered by the bat to the ball? Known Variables: (ball) mass…
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What is the Final Speed?
A man standing on very slick ice fires a rifle horizontally. The mass of the man together with the rifle is 70 kg, and the mass of the bullet is 10 g. If the bullet leaves the muzzle at a speed of 500 m/s, what is the final speed of the man? Known variables: (man) mass(m1): 70 kg (bullet)mass(m2): 10…
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What is the Mass of Water Collected?
A 5000 kg open train car is rolling on frictionless rails at 22.0 m/s when it starts pouring rain. A few minutes later, the car’s speed is 20.0m/s. What mass of water has collected in the car? Known Variables: Mass of train (m1) = 5000 kg v1 = 22 m/s v2 = 20 m/s Conservation of momentum: Pi – Pf = 0…
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What is the Speed of the Ball?
A 71 kg baseball player jumps straight up to catch a line drive. If the 140 g ball is moving horizontally at 29 m/s, and the catch is made when the ballplayer is at the highest point of his leap, what is his speed immediately after stopping the ball? Known variables: (player) m1= 71 kg (ball) m2 = 140 g or .140 kg…
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How much Torque?
How much torque must the pin exert to keep the rod in the figure from rotating? Calculate this torque about an axis that passes through the point where the pin enters the rod and is perpendicular to the plane of the figure. Known Variables: L: 80 cm or .8m M(of the rod)= 2.0 kg m(of the weight)= 500g or .5 kg…
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Magnitude of the Vertical Force
A 57 kg diver stands at the end of a 29 kg springboard, as shown in the figure. The board is attached to a hinge at the left end but simply rests on the right support. What is the magnitude of the vertical force exerted by the hinge on the board? Known Variables: (diver)m1 = 57 kg (springboard)m2= 29 kg…
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