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Q7.a bullet of 100g strikes a sand bag at speed of 1000m/s and get embedded after travelling 5 cm . calculate the resistive force exerted by the sand on the bullet |
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Answer» :Mass of bullet = 100g = 0.1kgInitial speed = 1000m/sDistance covered by bullet = 5CM = 0.05mWe have to FIND resistive force exerted by the sand on the bullet★ In order to find force exerted by the sand, first we need to find acceleration of bullet.Using third equation of kinematics :v² - u² = 2asv denotes final speedu denotes initial speeda denotes ACCELERATIONS denotes distanceHere final speed of bullet will be zero as it comes to rest.➝ 0² - (1000)² = 2(a)(0.05)➝ -1,000,000 = 0.1a➝ a = -10,000,000 m/s²Negative sign shows retardation!We KNOW that, Force = Mass × Acceleration➝ F = m × a➝ F = 0.1 × 10,000,000➝ F = 1,000 kN |
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