Question:
The time required to stop a car of mass 800 kg, moving at a speed of 20 ms\(^{-1}\) over a distance of 25 m is
The time required to stop a car of mass 800 kg, moving at a speed of 20 ms\(^{-1}\) over a distance of 25 m is
Show Hint
When stopping distance is given, first find acceleration using \(v^2 = u^2 + 2as\), then time.
Updated On: May 8, 2026
- 2 s
- 2.5 s
- 4 s
- 4.5 s
- 1 s
Show Solution
Verified By Collegedunia
The Correct Option is B
Solution and Explanation
Concept:
Use equations of motion for uniformly accelerated motion:
\[
v^2 = u^2 + 2as, \quad v = u + at
\]
Step 1: Write given values. \[ u = 20 \, \text{m/s}, \quad v = 0, \quad s = 25 \, \text{m} \]
Step 2: Find acceleration using first equation. \[ 0 = (20)^2 + 2a(25) \Rightarrow 0 = 400 + 50a \Rightarrow a = -8 \, \text{m/s}^2 \]
Step 3: Find time using second equation. \[ 0 = 20 - 8t \Rightarrow t = \frac{20}{8} = 2.5 \, \text{s} \]
Step 4: Conclusion. \[ \boxed{2.5 \, \text{s}} \]
Step 1: Write given values. \[ u = 20 \, \text{m/s}, \quad v = 0, \quad s = 25 \, \text{m} \]
Step 2: Find acceleration using first equation. \[ 0 = (20)^2 + 2a(25) \Rightarrow 0 = 400 + 50a \Rightarrow a = -8 \, \text{m/s}^2 \]
Step 3: Find time using second equation. \[ 0 = 20 - 8t \Rightarrow t = \frac{20}{8} = 2.5 \, \text{s} \]
Step 4: Conclusion. \[ \boxed{2.5 \, \text{s}} \]
Was this answer helpful?
0
0
Top KEAM Physics Questions
- A body oscillates with SHM according to the equation (in SI units), $x = 5 cos \left(2\pi t +\frac{\pi}{4}\right) .$ Its instantaneous displacement at $t = 1$ second is
Kepler's second law (law of areas) of planetary motion leads to law of conservation of
- Two capillary tubes A and B of diameter $1\, mm$ and $2\, mm$ respectively are dipped vertically in a liquid. If the capillary rise in A is 6 cm, then the capillary rise in B is
- In the circuit given in figure, 1 and 2 are ammeters. Just after key K is pressed to complete the circuit, the reading will be
- A plate has a length $ 5\pm 0.1\text{ }cm $ and breadth $ 2\pm 0.01\text{ }cm $ . Then the area of the plate is:
View More Questions
Top KEAM laws of motion Questions
- If the road is unbanked and the coefficient of friction between the road and the tyres is $ 0.8 $ , then the maximum speed with which an automobile can move around a curve of $ 84.5 \, m $ radius without slipping $ (g=10\text{ }m{{s}^{-2}}) $ is
- Two forces in the ratio 1 : 2 act simultaneously on a particle. The resultant of these forces is three times the first force. The angle between them is
- A body of mass $60 \,kg$ suspended by means of three strings $P, Q$ and $R$ as shown in the figure is in equilibrium. The tension in the string $P$ is
- Two equal forces are acting at a point with an angle of 60$^{\circ}$ between them. If the resultant force is equal to $40\sqrt{3}$, the magnitude of each force is
- Two blocks of masses 7 kg and 5 kg are placed in contact with each other on a smooth surface. lf a force of 6 N is applied on the heavier mass, the force on the lighter mass is
View More Questions
Top KEAM Questions
- i.$\quad$ They help in respiration ii.$\quad$ They help in cell wall formation iii.$\quad$ They help in DNA replication iv. $\quad$They increase surface area of plasma membrane Which of the following prokaryotic structures has all the above roles?
- A body oscillates with SHM according to the equation (in SI units), $x = 5 cos \left(2\pi t +\frac{\pi}{4}\right) .$ Its instantaneous displacement at $t = 1$ second is
- The pH of a solution obtained by mixing 60 mL of 0.1 M BaOH solution at 40m of 0.15m HCI solution is
Kepler's second law (law of areas) of planetary motion leads to law of conservation of
- If $\int e^{2x}f' \left(x\right)dx =g \left(x\right)$, then $ \int\left(e^{2x}f\left(x\right) + e^{2x} f' \left(x\right)\right)dx =$
View More Questions