Question
A rocket with a lift-off mass 10,000 kg is blasted
upwards with an initial acceleration of 5.0 m s–2. Calculate the initial thrust (force) of the blast.Solution
Given that Mass of the rocket, m = 10,000 kg Initial acceleration, a = 5 m/s2 Acceleration due to gravity, g = 10 m/s2 Using Newton’s second law of motion, the net force (thrust) acting on the rocket is equal to F - mg = ma F = m(g + a) F = 10000 × (10 + 5) N = 10000 × 15 N = 15 × 104 N
A vehicle travels 60 km at 40 km/h and returns 60 km at 60 km/h. Find average speed for the whole trip.
A man first travels 140 km at 70 km/hr and next 140 km at 35 km/hr. The average speed for the first 280 km of his travelling is:
- A woman drove for 5 hours at a constant speed of 60 km/h and then drove another 2 hours at a constant speed of 90 km/h. Find her average speed for the whol...
A person needs to travel 300 km. If he covered the first 30% of the distance at a speed of 60 kmph, then 3/5th of the distance at a speed of 50 kmph, an...
Two trains approach each other at 25 kmph and 35 kmph from two places 240 km apart. After how many hours they will meet?
Buses A and B are moving around a circular ground of radius 350 m. If the speeds of the buses A and B are 15 m/sec and 20 m/sec respectively, then what ...
'A’ and ‘B’ started moving towards each other at same time with a speed of 8 km/hr and 10 km/hr, respectively. If the distance covered by ‘A’ ...
A man walks at 5 km/h for 2 hours and then at 4 km/h for 1.5 hours. Find the total distance covered and his average speed for the whole journey.
- ‘X’, ‘Y’ and ‘Z’ can complete one lap around a circular track in 10 seconds, 15 seconds, and 20 seconds respectively. If they all start from th...
A train covers a distance of 80 km at the speed of 55 km/h the next 50 km distance covers with a speed of 40 km/h and last 60 km with the speed of 80 km...
Relevant for Exams:
